I don't know if one can ever forget in these situations. Forgiveness is a individual matter. I personally couldn't ever trust them again, I tried and thought people deserve second chances, but some things in life they just don't. To suspect a prior incident now that the trust has been broken carries a lot more weight. You know him better than anyone, and you will be the one who has to deal with the fallout if it doesn't work. No simple answer sorry, maybe see a T to figure out more clearly how you really feel about trusting him again. Hope you got a good guy who just made a major major mistake and it won't happen again. I feel for you. Best of luck.