toh- Right now you need to what is best for you. I felt that NC was better for me because I ended up feeling stronger being away from my H's craziness when he was angry. Even though the anger and craziness seem to be going away, I still do not contact my H. I let him contact me. I understand your dilemma where you don't want to be a part of the drama but you don't want him to latch on to the OW either...but that being said, your H isn't happy...what makes you think he is going to be happy with the OW? Now, I am no expert and my H doesn't have an OW that I know of, but I would still let my H go to figure out that the OW isn't going to make him happy either. He needs to find his happiness within himself again before he can be happy with anyone else.
When my H left, he said he was empty inside and that he had nothing left to give. The OW right now is no pressure, no responsibility...that is what someone in MLC wants because they really have nothing to give. Is there anything you can do besides going NC so you are no pressure, no responsibility for your H?
Just as a side note, I do know what it is like to have a H involved with an OW...my first H ended up married to the OW but it took her getting pregnant for me to give up...and it took another pregnancy for him to finally marry her. I don't believe they are happy people to this day. Anyway, I know it hurts like h@ll to have your H leave you and cheat on you but remember YOU WANT A MAN THAT WANTS TO BE WITH YOU BECAUSE HE WANTS TO...not because he is obligated to.
You have to do what is best for you but from my point of view I would think that would be letting him go as much as you can so he can figure himself out.
