The fact that he is turning down sex is very bizarre unless he's got something going on on the side. My guess is he is emotionally immature and expects to get the same feelings from your marriage as he did the affair. Affairs are secretative, exciting and dangerous and the feeling you get is like a drug. You guys have been together for a really long time so the reality is that he is not going to get that high he is looking for right now.
You really have two options:
1. Wait it out and do 180s, detach and GAL and see if he comes around. Most people suffer immensely in this scenario because they are watching their spouse like a puppy dog at a table for waiting for scraps.
2. You separate making clear that you need some time to figure out what you want and that you will be treating this like a real seperation. You don't have to date if you don't want but you need to make it clear that it's an option.
Statistically speaking men are less happy then women after divorce so you have that in your favor.
It's very important that you stop trying to argue your point and validate his feelings because you are in no way going to be able to convince him of anything right now.
