"He can get it up with medicine and does so to pleasure me," is problematic because if he's not benefiting from the sex it will become "work" and he'll tire of it and quit, pushing you to exercise the sex without feeling option.
Human moral codes are all over the spectrum so it sounds like his are out of synch with yours. You'll have to figure out how much that affects your relationship, especially if you're a person who only has sex with a person about whom you care (violating his cheat without caring rule). I wonder if he is really okay with cheating without caring, i.e., did that work in a previous relationship or did it kill the relationship. People often say similar things, but then they can't believe you don't have feelings for the third party.
Finally, from your description it sounds like he's internalizing his emotions. He may reach a point he can no longer do that and will explode in a murderous rage. Don't be there if that happens.