I feel like my life has been a lie

I broke up with my boyfriend on November 29th. I thought I was healing, but new information surfaced recently that has re-opened this giant wound.

J. (22) and I (20) had been together for 2 years, one year and two months of that we were living together. He had a job for approximately 2 months of that time frame. I know it was stupid of me to keep him around, but he's a giant guilt trip in human form. Anyway, I found out about a week ago that he had been cheated on me right after we moved in together. I confronted the girl (out of anger) only to find out that she had a list of other people he had slept with. one of them being my best friend.

I found that part out a few days ago, right before I went to visit my mom's house for Christmas. So here I am, thousands of miles away on what should be a fan-fucking-tastic trip, and every few minutes I get this massive adrenaline rush, knowing how all of my friends have betrayed me.

I took care of him, supported him, cooked and cleaned, I rubbed his feet and I made sure that I gave him everything I could (which attributed to massive amounts of my paycheck), and in return he mooched off of me, hurt me, cheated on me....

I know I was dumb for letting it continue, but he's a charmer and every time I brought anything up he flipped it on me to make me feel bad.

I don't know how to deal with something like this. I'm tired of hurting, and I don't know how to heal from both of their betrayals. I'm afraid I'm not going to be able to trust anyone anymore. help.....

tl;dr scumbag mooching boyfriend cheated on me with my best friend; hurting badly; don't know how to heal. plz help.