I don't think your H is a "bad guy". I don't think my H is a "bad guy". I think they are both behaving badly. Very badly. I think they are both behaving in a selfish way. I am not sure it is up to anybody to judge who is "good or bad" at their core but it's not hard to see (you, me, any LBS really) when behavior suddenly shifts from "good" to "bad". I don't think my H or your H sits up at night thinking of ways to hurt us more. I do think they are so blinded by selfishness and weakness they simply can't see how destructive they are.
Affairs are very, very powerful things. I agree that our husbands are weak. Your H left when you got pregnant and my H left when I got sick. And neither of them were man enough to leave on their own accord... they both left once they knew they had a "backup" (OW) waiting in the wings.
Not that this makes it hurt any less because it doesn't. But I have to remind myself often of just how weak my H is.
Your H reminds me so much of mine with the "this is the hardest thing I have ever done" and "I am still not 100% certain" and my ALL TIME FAVORITE "I am just trying to be honest". LOL! Affairs and honestly don't usually go hand in hand.
My H for the first time in a long while is starting to contact me again via text, e-mail and now the postal mail with his "charming" ways. Again, it is another illustration of how terribly selfish a WAS can be. You are living with the woman you had an affair with while married to me yet somehow you think it is okay to keep contacting me. It shows ZERO regard for *my* feelings and really is only done so my H can feel better. Sort of like yours is doing.
While it is NOT easy I would just go about your business, don't allow him to linger when he comes in, regulate him to the entryway, be fabulous and really remove him from your life as much as you possibly can aside from issues with your son.
I have dated a few really great guys but after a few dates I always feel terribly conflicted and "not right" so I know I am not really ready. If you are ready then get out there! You will know what feels right or what doesn't.