Even though it's killing me should I forgive him?

I was going to make 2 years in december with my boyfriend. In June we had a big argument and I left to Puerto rico for about 2 weeks. I made it seem like if I was leaving with a man because I was sick of the relationship even though I loved him. I stayed at my aunts house and I didnt do anything wrong. When I got back we worked things out and we got back together he stood with me the whole summer until 1 day in august I found a sonogram in his wallet of a 8 week old fetus, He convinced me that it wasn't his , that he picked up that piece of folded paper to write down a number and that he didn't know that that was a sonogram,I ( being stupid believed him) the day after thanksgiving he took a shower I checked his wallet and I found another 1. He confessed that while I had been In puerto rico he slept with a women and she became pregnant. he blamed me for making it seem like i was with a man in p.r when I wasn't.this is destroying me . i have so much anger in my heart because he lied to me. I know that he loves me but I don't think that I will ever forgive something like this. Do you guys think he deserves another chance? Help me please.