It sounds to me that you are looking too much to your H. You are sounding fused.
I suggest you get on with your life and see whether or not he is able to follow and stand up and be a man.
I agree that transparency is a must, and his lack of it is worrying. I personally would see that as a big red flag. However, there is a possibility that there is something going on that doesn't involve any OW. Maybe he has job problems, financial worries,is seeking help for depression. It could be any sort of thing.....or of course it could be OW.
Whatever the reason is, STOP doing things to impress your H and do things for yourself and your children. You are making yourself unhappy trying to attract his interest sexually and at the same time you are showing him that you are vulnerable and available and waiting for him on his time scale. He has you hanging there.
I don't know about your experiences at school, but at my school, the popular kids were the ones who didn't appear to care what others thought about them, but they did what they wanted to. Their confidence oozed out and it made them attractive, (even though often they weren't the most physically attractive of the students). The ones that looked to them for comfirmation in order to know they were ok seemed slightly desperate. Do your own thing and just see if he follows. Be pleasant but don't put yourself out for him.
You need to let this frustration and anger go, ( no easy thing I know - I would want to punch him), if you are to give this a chance. Even if he was still seeing OW, it isn't about her, it's about how it makes him feel - he is using her if he is seeing her and she will end up paying the price.
In my gut I feel he is trying to make you make some sort of decision so that he can 'blame' you for the outcome. Don't resort to that. Let him make his own decisions and you make yours. Take the high road and don't resort to underhand comments - they may feel good at the time but later on one realises they were just silly and will come back and revisit you tenfold at some time in the future in the guise of 'You can't let go' or ' You will never forgive me so what's the point in trying?'. Don't let him force you in to a corner.
You need some space and you need some YOU time.
Saffie me 46 H 46 M in 1986 D20,D18,S16,D13 H's A 01/05 to 07/06 H recommitted to M 07/06 renewed vows 09/06 Going from strength to strength