HI May - until he moves past the OW he is not thinking clearly, don't expect him too - he knows what he is doing is wrong and is justifying this within himself. You described him with "entitlement, lack of empathy, and inability to take responsibility for his own actions" that is probably EVERY H that is in the midst of having an affair (and I also would say pre and post). You have alot to lose by giving up on him though...you still love him, otherwise you would not still be involved here, he is the father of your girls, you have history, etc - maybe its because you still see a marriage with him as a possibility and really ... because you still love him.
You know the saying, behind every great man is a great woman, I would dare say this as well... behind every broken woman is a broken man. That is going to be my new tag line, because its so true, especially here on these boards. Do not expect alot from him while with an OW, actually expect nothing - because he will lie, drop breadcrumbs, whatever it takes to keep you on the line, sadly. But I have the belief that you can win him back with a word.
Do the DB, be kind, don't engage in R and absolutely go on this trip with the mentality that you will enjoy it, you will bond with your girls, and ...he will be in contact with OW. Did I tell you that on my trip the OW was trailing us with a girlfriend, same places down the coast? (all later found on her social media - though I didnt know at the time). Just decide now that you will not bring it up or spend any effort/time on arguments (especially about the ow).
I will always encourage you to hold out, and when you feel like you can't - hold out another 2 weeks. Here is the 2x4 I guess: we did not get to this spot because we were awesome wives, so in some way you need to make your changes, and show him in actionable ways so that he can see that you did make changes for the better, that being married to you is a possibility. Engaging in cr@ppy behavior is only going to make the ow look that much better.
I am rooting for you and your marriage! Not to say that it won't take work. I still cry when "new" things come up with him (check my thread, I wont hijack) but be positive - IF you still love him, this is hope. I truly believe that.
M:50 H:49 D:16 S:13 M:23 T:25 BD: Feb 25th 2020 EA/PA: Dec 2019 - June 11, 2020 Behind every broken woman is a broken man...