My boyfriend and I have been together for five years, have lived together almost that entire time and have a five-year-old son together. I work part-time and go to school full-time, to try to make a better life for us. He works seasonal jobs with his stepfather and takes care of all of the expenses during that time. About three years ago, I noticed his behavior was a little bit odd each time I would come home from work, I work the night shift. I felt in my heart that he was hiding something, so I waited until he was away from his phone to investigate... About six months previous to this, we decided, as a couple, that we were not going to use facebook anymore because it causes too many problems in relationships. So, he asked if it was alright with me if he could create a facebook profile that was only for the "for sale" websites, to see if we could snag any deals. I agreed, oblivious to what his true motive was. Back to the day I went through his phone, on a hunch, I found that he had been consistently "facebook stalking" his ex-financee courtesy of his phone history. I confronted him about the situation and asked him if it was alright if I contacted one of my ex's because I am feeling lonely and you don't pleasure me.. he looked at me like I was stupid, and said what are you talking about? I said, "I seen that you were looking up your ex on facebook, do not try to lie to me." He finally admitted to it, and by this time I was so upset all I could say is "But why? what's wrong with me?", and he responded that he missed his ex,and wishes he could still be with her. That really hurt me, and still does three years later, because I wonder if he wants to be with her, and I was just some sloppy second choice. What hurts even more is that I discovered after he looked at her profile on FB, he was watching "chubby porn", and his ex was a bigger girl.. I'm not a bigger girl so I know he is still sexually interested in her. It is affecting our sex life dramatically, I feel like he imagines that he is actually having sex with her instead of me... I try to avoid having sex with him because I feel so depressed afterwords. I have never told anyone about this because I feel dumb that I could still love him after it was clear that he does not love me the same way back. I just need some advice about how to cope with this because it is ruining my daily life. I have asked him mulitple times if he has spoken with her or seen her, he just gets angry and says No! But I feel it again in my heart.. 

Any help would be appreciated... Thank You,

-A