I would suggst him getting a test for diseases before even thinking about being intimate with him. If he was with a prostitute I hate to think about what he could have been in contact with.
About the sex issues. You just have to be open and honest with him. Let him know point blank what you need from him in that department. Let him know how you enjoy sex. Also let him know that he isn't doing it for you in the bedroom. Try to do it gently but do let him know. Don't make excuses about the child support for him. If he was any kind of man he would pay that voluntarily.
