Do his parents know that hes involved in an affair? How have they reacted? I think that if you do write a letter to them, it should just be plain, factual and show that you hope that the marriage can be saved. Stay away from trying to get them to take sides, or even asking them for sympathy. Then, I would go dark about it to them. If they do already know, I would just tell them that you are hopeful that things can get better, and you are trying to get your things together for the move. Stay upbeat and dont talk about your sitch to them. If they bring it up, and you change the subject and they keep at it, politely tell them that you would rather not talk about it.

I agree about the bars, if you have been unfaithful in the past, the last thing that you want to do is look like you might be on that road again.

I guess I gave the wrong finger to the wrong man...