your age does not matter, under 18 its called being abused, over 18 it is called being raped, call it what you like both are wrong, hey even if you did have an affair it does not give him the right to take sex from you without your full consent, even marriage does not give a man that right!
of course he denies abusing you, he has had to for so many years he probably does not know what is the truth anymore. the fact is he is still upsetting you and that is wrong, like i said above keep any texts he sends you, use them to prove what he is still doing to you, it is the only way to stop bxxxds like that.