I need some advice.

Two days ago, I was closing down my boyfriends computer for him while he was at class. he left open his email and I was going to go do some stuff online, so as I went to type in an address, I saw a post that he had made on Craigslist. I was not snooping, I trusted my boyfriend. But, I saw this post, he has made it earlier in the morning before I got there. It was a post asking for NSA sex with an older woman.

I know that nothing happened, because he had just posted it in the morning and there was no responses. Deep down, I actually think nothing would have happened, I think he is too scared to meet someone offline like that for sex. We ourselves met online, we talked for about 2 months before we met, we were both really nervous.

When he got back from class, I confronted him about it. There has been some sexual problems in our relationship, and he blamed it on that. Every time we have sex, he cannot orgasm. No matter if it is through oral or just sex, he can't do it. We have been together 7 months now, and in that time, he has only orgasmed maybe 3 times. I know this is frustrating for him, and that is what he told me. He told me he thought maybe if he could do it with another woman, then he could do it with me. He is 20 years old, and healthy. I am the first person he has had sexual relations with.

I just feel very very hurt. Before this, I never had any doubts in him, now I can't stop doubting and I dont want to be that kind of girlfriend. but, I love him, I really do. And, i do think that him not orgasming is making him very frustrated, and we talked about it. Usually, when we are doing things, if he goes soft, he will just focus on me, but we never really talked about it. And now we did, and we were both crying, and we promised to communicate more with it, and how to work with each other.

I also think that he may be depressed sometimes. He works night and has a horrible time sleeping he says when he is all alone, he thinks bad things, like how he isnt doing anything in his life..and then about his sexual "failure."

I want to work this out, because nothing happened, and I think he did it because of how he feels about his sexual performance. I just don't know how to go about starting. he has been very open to me, when I asked him questions about it, what he was thinking and all that. he never yelled or got defensive, he only answered my questions and cried with me.

Has this happened to anyone one else? Or have you yourself done this? Thought about cheating but didn't do it? Or caught someone before they did? how did you work through it?