<human>: My boyfriend and I have been together since last August, and we love each other very much.

From January until April, he spent some time in jail for non-violent charges. During that time, I began a sexual relationship with someone and eventually ended up telling my boyfriend. He forgave me eventually, though sometimes I feel like he still thinks about it.

Recently, however, we have begun to argue more frequently, mostly about me "looking sad" or spending all the time in the bedroom when he's in the living room with his friends. He also says that I don't look at him in the same way anymore (i.e. full of love/googly eyed). 

We also don't have sex as much. I still get a lot of pleasure from sex with him but a lot of times I'm just not "in the mood."  He will try to initiate and then if I refuse, he immediately asks if he can go masturbate. You can jack off, but please don't let me know about it. 

I'm not sure what caused this change in our relationship or my sadness, but it's making the both of us miserable. I have tried to smile and be more tender and sweet with him, but sometimes I feel like it's not enough for him.

May I also point out that I am his first major relationship and his first experience with sexual intercourse, and he lied about me being his first for about 3 1/2 months.

Any pointers as to how to bring back that original feeling we had? Does our problem and his emotional neediness have anything to do with his inexperience (though he is a very satisfying lover)?

Can you condense the text into a few key points?
<bot>: I've been very down in the dumps and not wanting sex for unknown reasons and it's making my boyfriend sad. What's wrong with me/us?