[Hopeless Dork]

There is nothing that you can check on her body physically that will tell if she had sex the night before. And to be honest there are no emotional symptoms you will be able to check on someone that is pathological as they don't express guilt the same way.

[Hopeless Dork]

But just wanted to add here... what makes you THINK she is cheating? What are some of the things leading you to be believe this might be happening?

Because it could be that nothing is happening and you are being paranoid --- so please give us some more background for better more fitting opinions

[Tzoto]

Her new best friend at work, whom is male, and let me point out that she is 18 and he is 35...And she has spent the night there a few days in a row, while his wife has been out of town...

[Hopeless Dork]

Does she have any legitimate reason for sleeping at his house?

[Hopeless Dork]

Unless she is homeless and has no family no friends and you can't put her up I don't see any reason in the world a girlfriend would spend the night at some married mans house while his wife was out of town.

If it was an emergency, car broke down, intoxicated etc... that would maybe excuse one day but 2? Why is she telling you she is spending the night with him?

[Tzoto]

Like I said, she said "Best friend," and that they just want to "Hang out." Not much more to say is there?

[Tzoto]

Oh, and we live in the same place, so no homeless scenario.

[Hopeless Dork]

Is this something his wife is okay with? Does she ONLY sleep over with her "best friend" when the wife is not there?

I can understanding 'hanging out' with a best friend but sleeping over is a no-go for someone in a relationship -- there is no reason for it, not in my opinion.

So I'd start there, whether or not she is cheating, having sex with him or just cuddling, whether they are sleeping in 2 different rooms and think yuck about becoming close... the problem here is that a woman in a relationship has no business sleeping at a heterosexual male friends house when his wife isn't home. Its not appropriate and if it bothers you (as it would any rational person , its not a jealousy thing or an insecurity thing -- it crosses the line of being way innapropriate) than its a sign of disrespect that she would do it anyway knowing you have a problem with it.

Whatever her friendship with him entails it should be able to be conducted during reasonable hours with no sleep overs... are you ever invited to hang out with her and her best friend? Does he come to your house?

Has she always had him as a best bud or is this recent? How does she treat you? Does she make you feel loved and special or do you feel like an inconvience?

I understand that you love her, can you explain what it is about her actions that inspire you to feel that way about her?

And what it is about her actions that would in anyway show you she feels the same?

[Tzoto]

A lot of questions...

But I do not even think that the wife knows about this.

It is a recent work friendship.

I have not asked to hang out with them both yet, he has been over to our place and they were not all over each other, but something was still off.

And she goes back and forth like most people in the Love/Hate relationship.

And I have known her for about five years, and we dated for almost four (Almost, because we had some breaks in between...). And I have loved her since the first day that I hung out with her in high school, and I know that this sounds corny, but she really is one of only a few people that understand me (As in I like to have deep philosophical conversations, and most people want to talk about when they are next going to get "ed up." While she will hold the conversation with me for several hours, literally.)

[Hopeless Dork]

It just doesn't sound good, hun. Have you told her that you'd rather not her sleep at his house? Why can't she come home after they hang out. Heck even if she were having an affair with him its not as if they need all night.

But her sleeping over does lead to the impression that she may be having an affair, and also may be becoming emotionally attached as well.

I mean he's married so when his wife comes home I guess she won't be sleeping over any more. And she may not be having an affair she may just very well lack reasoning or respect for your feelings by thinking its okay to sleep at another man's house while his wifes out of town.

I am waiting for someone else to chime in because in my heart and mind I don't see the logic behind her actions.