Menofhonor

I am not sure if this is the best place to come for advice but I figure I will give it a shot.

I have been married for over 2 years now and things havn't been going so well lately. My wife and I had a huge fight a few weeks back and she said some really hurtful things. Not the name calling things but shit that really hurts like she isn't sure if she has ever loved me and maybe we are just better friends. I just found out during that fight that she had slept with someone while we were dating but before we were engaged. Now she has this close guy friend that has really been making me jealous but my wife doesn't seem to care. They are in the same graduate program together. The things that she has done to make me jealous are she parties with her girl friends and him and another guy or two at least once a week and I am not invited. They went on a research conference together and one night stayed in the same hotel room with just the two of them for cost reasons. They ate at a fancy resteraunt together with just the two of them during this conference. They sometimes hang out at his place to watch movies with just the two of them.

Another thing is that she really hasn't felt the passion for me for probably over 3 or 4 years now. I hadn't noticed how bad it was until I started to look back. By passion I mean she is very rarely in the mood to have sex and rarely ever wants to kiss me more than a peck. When we do have sex I dont always feel like she is into it.

First of all am I being too paranoid about her and this guy and if I am not what should I do about it.

Secondly should I stay in this marriage if I still really love her alot and I know I mean alot to her in spite of the fact that she really doesn't have passion for me. By the way we have been together for 5 years and we are in our low to mid 20s