I would not look at the trust, I'd look at the repeatedly. If we do something repeatedly that is telling us a lot more than mere words can. I would not trust someone else to not cheat if they had cheated on me more than once but I would also see the whole as a warning to me to look at my attitude about the person, how I personally define "cheating" (some people consider talking to someone of the opposite sex cheating), and how the other person does/does not treat me with love and respect. I believe actions do speak louder than words and there's a whole lot of other actions possible in a relationship than just the sexual. I don't believe someone can treat me with love and respect and cheat me at the same time (by which I mean have sex with another adult, while hiding/trying to hide it from me).

If someone lies/hides from me, they cannot get back my trust. If I were to lie/hide from another, I'd get a clue that I did not love that person and was not being respectful of them and I'd go work on myself, by myself to learn not to lie/hide from those with whom I wish to have intimate relationships.