Deb, Calm down and take a breath. Think about the pros and cons of finding out if something is going on. If you did know, could you do anything about it? Would it bring you closer together. I nothing is going on, would it bring you closer if you confronted him?
Believe me I know how hard it is to not think all those thoughts. I still wonder waht XW is doing, where she is, who she's with, does she even think of me? It hasn't helped me yet to know any of this.
Your H seems to be trying to change to make the M better. Give him the benefit of the doubt. Would your sitch be better if he left you to be with OW and wanted nothing to do with you. Absolutely no communication. Please use the communication you have and turn it into a positive.
If you find out later he is playing you, you will be better equipped to deal with it. Good luck. I will be praying for you.