My wife put off having anal sex with me for 23+ years. She finally agreed several months ago - and is now quite enamored with it. We can't go back - but it seems such a waste.
It's 60% mental, 20% lube & 20% patience. You have to want to enjoy it - or it'll never work. Think of it like when you were learning to drink beer. At first it didn't taste that good - but once you get use to it, it's quite good.
Lube and patience will help you avoid pain - speaking of beer (or the adult beverage of your choice) - will help you relax which is also useful.