Justconfused
It is normal to feel the way you do right now. It takes more than a few months to get over and affair and the hysterical bonding phase can be very misleading emotionally. This can lead him to think that things are/will be fine if not better than before...perhaps he even feels that it validates his actions further in the sense that you woke up to the fact that his sexual needs were not being met and are trying to satisfy him better. The problem is as you have said, is once this phase is over your left with the reeling emotions that you could not quiet process at the time. It is quiet normal to not really feel true anger and hurt over the affair till months later. You go into survival mode and your trying hard to protect what you feel is yours....problem is your often fighting for the booby prize.
My issue with this is not what you are going through (as I think it's completely normal) but it is how is responding to it. Like other posters have said he feels he is entitled and is making you feel guilty over the sex rather than supporting you and understanding. You are not denying him sex out of cruelty, you are going though emotions that even while he may not completely understand he could at least sympathize with you.
It really takes an awful lot of time to get past the mental images of him with the OW....it tortured me for what felt like an age. It is also a gradual process and does not happen overnight and only happens once you being feeling secure in your relationship again. He is a key factor in all of this, if he can't make you feel secure you are unlikely to get over this together.
I don't doubt that sex is uncomfortable for you right now as I am sure when he does a certain thing or touches you a certain way you find yourself wondering...did he do this with her, was he the same with her, was she better than me, did he enjoy it more etc etc. These are horrible feelings to have to endure because you can never know, and he is likely never to tell you how it really was even if you have discussed it. It takes a long time and you cannot force yourself there, but you eventually get to a point where you accept that it happened and as much as it hurts your decide to just let it go because its not worth dwelling on anymore. You will get there one day, but he has to help you through if your going to get through this as a couple.
I feel your pain and I wish you good luck for the future 