Neela,
Time-outs huh??!!! There is no other way to say it...They're a bitch. Been there, done that.
As for the infidelity, well thats ultimately up to you to decide where your boundaries are. I do recommend clearly stating what is a deal-breaker as to your relationship, and then actually sticking to it if the "worst" was to happen.
PTSD sufferers are not fools. They know when they are on a good thing, they are human after all. Lets face it, if you have a ready made excuse for "bad" behaviour you can pull out whenever you want, and your partner will then excuse it.... well... no guidelines.... expect trouble!!!!!! And that just doesnt only apply to PTSD sufferers!!!!
Each time taking a break comes up, set down rules. Both parties are to work within the decided guidelines. It then decreases worry, on both sides!, and if either party breaks the 'Rules', the behaviour is punished accordingly.
I have been at times too soft, and too hard. In matters of the heart nothing is simple. In matters of self respect.... well, just dont ever lose that.
Hugs
Ryair xxxxxxxxxxx