<human>: We've been dating for 3 years.

This all started at the beginning of our relationship. I noticed he had a really attractive female friend, and I asked if anything ever went on between them. He said no, but I still had my suspicions.

About a year into our relationship, I was still wondering, so I snooped on his personal computer. He was looking at her FB and porn sites at the same time. I figured maybe it was just a weird coincidence and didn't give it all that much thought. 

Fast forward to the present day. I was using my bf's computer and I snooped again (I know it's horrible to do) and found out he's been using FB and Twitter pictures of his hot female friend and MY hot female friend to get off. He's been using their fully clothed pictures plus porn to get off. I approached him and he completely admitted to it.

I feel horrible. They are both much prettier than me and I just feel so grossed out he's been clearly doing this for our whole relationship. Why not use porn like a normal guy? Makes me feel like an ugly piece of shit.

It really hurts me that he was jerking it to his female friend. I always KNEW that there was something going on with them and he never admitted it. I now know my suspicions were true and he has some creepy crush on her.

Summarize the given text in a few sentences.
<bot>: Boyfriend uses pictures of his hot female friend (who I suspected he was obsessed with) and my hot female friend to jerk off. I feel horrible, like I'm his third choice and he really wishes to be with them.