Short answer: Decide whether your discomfort has any basis in reality. Talk to her about it and either ask her to explain her actions (if you think something's going on) or that you trust her, but you're still uncomfortable (if you think it's just jealousy). Long answer: Be logical. Look at the situation with as clear a head as you can and decide whether your discomfort is based on what you know about the people and situation, or whether it seems to be unfounded jealousy. The opinions of neutral friends can be invaluable here. Don't speculate about things you don't actually know! Your brain will always feed you a worst-case scenario. Here are some things to consider: How well do you know the ex, and the friendship between him and your girlfriend? If it's not well, try doing something with the two of them (which could include other friends) to get a sense of the vibe between them and what kind of a guy he is. You may find that you trust him a lot more afterwards, or you may not like the looks he's giving her. How long ago did they break up, and under what circumstances? Either or both of them could have unfinished business or a feeling that the relationship should have gone differently. On the other hand, they might have just decided that they suit each other better as friends. Do you trust your girlfriend? I can't advise you on this one, it's up to your own experience and gut. Don't give an automatic answer, sit down and think about it. When you've reached a conclusion about whether your worry has any basis, talk to your girlfriend. Don't be angry or accusatory, but tell her you're uncomfortable. If you think something might be going on, tell her what makes you think so and give her a chance to explain. (Whether you buy the explanation is up to your knowledge of her.) If you think you're being needlessly jealous, make sure she knows that. She'll almost certainly appreciate the admission and may well take it upon herself to reassure you. Unfortunately, recognizing discomfort as unfounded doesn't make it go away. It just stops you from doing something you might regret. In any case, it's a difficult situation; good luck.

Tell her how you feel. Tell her that it bothers you and be as polite as possible--after all, she's not a mind-reader and can't tell what you're thinking, if you don't tell her. The key to any successful romantic relationship is open communcation and honesty. If you don't have both, then you won't have a successful relationsihp. If she respects both of your relationships, then she will be more than willing to listen to you. I hope that helps and good luck!

break up with her its dont be an idiot she its cheating at you cuz i am hers ex

SAME SHIT HAPPENED TO ME :(... HE IS AN ASSHOLE TOO... ITS NOT REALLY A GOOD ANSWER BUT ITS NICE TO KNOW YOUR NOT ALONE...

Not a mind reader? What...is she retarded? She slept over at her ex's and she doesn't know what her current boyfriend is thinking? I bet she knows what I'M thinking! I bet everbody reading this knows what I'm thinking. Movin' on....

Talk to her about introducing one of her female friends, that way you and he can tag team them both.

She should stop seeing him or stop seeing you. Simple as that. If she is undecided or wants it both ways it will cause you endless pain. If you ask me she's probably still sleeping with him. Be kind to yourself and break it off. You don't have to take that kind of crap from anyone.

Tell her how you feel. As long as you don't make a fuss about things like her staying overnight at his place, she will continue doing it. Dude, do you really expect her to tell you she slept with him? Come on. You need a reality check. If she really cares for you she will take your feelings into consideration. If she doesn't care what you think you need to move on.

Tell her to check it or bounce yo...

First, trust her until she gives you reason not to. Second, tell her honestly that you're not comfortable about this. Be prepared to let go if it comes to that.

I just went through the same thing.....seeing this woman for 2 weeks...fell hard for her quick...she initiated the first kiss....had me stay over at her house (with no sex)...I knew she was still getting over a previous relationship from 9 months ago, told her all along that I could be patient because she was worth it... She kept telling me that I shouldn't get to into her tho....every time the kissing started to get passionate, she'd tell me to stop, saying"it's going to lead to bad things".....told me that we couldn't have sex yet or it would ruin everything....even took me to her parents for christmas the other nite.....same nite, I was asking her something....and got the answer....."yes, she was still sleeping with her ex since we started seeing each other.....I was aghast.....I can't even get mad at her....told her that I couldn't believe I was so stupid....told her that I was already falling in love but had been trying not to say it, because I knew she would get freaked out...after we spent that night together...I was just stewing in madness all day...that nite I slung some alcohol-induced insults at her via text msg....now she won't talk to me at all..... I regret my actions because I still really like her, but would it really have mattered? She had been playing me...whether intentional or not....I knew I was the rebound guy from thee start. Now all the awkward moments where she couldn't look me in the eyes, or when she would be a little stand-offish make sense. It sucks......I totally screwed up by getting upset...and there's nothing I can do to change it. Feel like if I really loved her, I could look past it...but everyone has told me what she did was shitty, and that I deserve better. Now I have no choice but to move on.

Tell her to stop seeing him at together. I had the same relationship with my ex then he told her never to talk to me again and she listened so it could work for you too.

Break up. If she cared about you she wouldn't do that. I wouldn't even waste my time talking to her.

Ugh, everyone's so quick to say "dump her, she's not worth it". My boyfriend and I both speak to our ex S/O's, but spending the night at his house is crossing the line - tell her (nicely) that you don't feel comfortable with it, and emphasize that it's not an issue of you not trusting her, that it just seems inappropriate that she's spending the night at his house instead of with the guy she's dating.

i have had the same experience. my girl clames nothing ever happens, however her ex when she is looking hawt will always make comments about it. that right there tells me he is still attracted. then one day i went over to his place, she was getting ready. when she walked out in the room in nothing but pantys i told mysels even if nothing happens. my girl is MY GIRL, no one else deserves to see this. so i told her how i felt and that i was her guy. if she continued to sleep over at his place then our relationship is over! it contradicts what we have together. if she truely loved you she will uinderstand, if she dont she probly has feelings for this guy only its not strong.

Tell her how you feel. Remember that friends is one thing. Hanging out and definitely "sleeping over" is too much. That you trust HER, but not him. That while you trust her, that her sleeping over erodes that trust somewhat, and you don't want that to happen.

This can't be true, why did she sleep at his place, was she drunk and couldn't drive home ? Did he throw a party or something ? Tell her, don't go to his place anymore.

you should tell her it bothers you and if she's respects you she wouldn't go over there anymore. that sounds pretty suspicious. why was she there anyway? and i'm sure if it were reverse she wouldn't be happy either.

It's HER relationship. You should not have a say, unless she wants you to.

Tell her and if she insists on continuing this way . . . you know what to do.

very rude and in considerate of her to do so even if there is still nothing between them. if that happened to me i would lay down the law and if that didn't work, get another gf.

If you're not comfortable with somebody's lifestyle, DO NOT date him or her. It doesn't have to be complicated, you know.

im a jealous type but that prevents girls from cheating on me. im not saying she is cheating on u but she might be temped to. i say if they split then they shouldnt be friends. i dont date girls who are still friends with exs or who have alot of guy friends

tell her the truth that you aren't comfortable so you don't haft to break up with her if you like her

I'm not comfortable with that either lol Seriously discuss the matter with her, tell her how you feel.. If she loves you she will do whatever pleases you but if she ignored your feeling & repeated the same thing then LEAVE HER and don't look back, simple!