<human>: I am in a long distance relationship with my BF of 6 months. He is a wonderful guy, sweet, caring and has never done anything to show that he is untrustworthy. 

Before we got together I had a brief relationship with a guy that in short was a giant douche. Shortly after I began dating my current BF he informed me that he had cheated on me when we were together. I shrugged it off though it affected me a little bit because of course no one wants to hear that they've been cheated on. After that I asked him not to contact me again. 

A few days ago the ex contacted me through facebook asking if we could be friends and if I was mad at him. I told him I wasn't interested in being his friend. He then sent me a long message trying to justify his cheating, explaining how and why it happened. He said that no man would be able to turn down the advances of a beautiful woman after having a few beers and babbled on about how all men cheat, how it's inevitable and so on. I didn't reply and blocked him on facebook. 

I've always been a trusting person. When I get into a relationship with someone I trust them until they give me a reason not to. But now my trust and confidence is shaken. He cheated on me right under my nose. I keep imagining how easy it would be for my current BF to cheat when he's so far away from me. 

Tonight he told me he was going out with his mates to have a couple of beers and my heart sank. I feel so panicked that I could almost cry. 

I haven't brought this up with him because I feel it's completely unfair to not trust him because of my ex's actions.

How do I get over this fear?

Provide a brief overview of the text.
<bot>: ex BF confessed to cheating, told me all men cheat and that I should accept that. This has unfairly been affecting my trust for my current BF.