My H also 'uses' the fact that he is an amazing father to receive 'kudos' from women. I told him a long time ago that women, especially married w/kids, eat that stuff up, love seeing a man so involved with his kids.
Speaking about cringing, I look at couples all over the place and think "Could I trust that woman?" or "I wonder if that man has cheated on his wife?". I never thought these type of things before, never lost 'faith' in the basics of life.
I agree with you about crossing the line sometimes, and can totally see how innocent people start up meeting people online because they are lonely (not here, chat rooms and things like that) and then it leads elsewhere. That is what happened to my H, he became the caregiver, stayed at home, fell into my routine of playgroups (going through a MLC and also a 'breadwinner' thing), met OW (my friend before all this) and she wasn't happy in her marriage. They became friends, met emotional needs that WE should have been meeting (or allowed to meet), then the physical stuff happens. I know my H never meant for this to happen, but he is responsible for his actions and could have said "No" at any time.