Ass play??

Sooo I just started seeing this a old crush from college who I never thought I'd see again anyways we've been having sex which is mind blowing. But a couple of nights ago I was giving him head and he asked me to...lick his asshole😒. I told him no way that's fucking gross he said okay flipped me over then started licking mine...he brought it up again last night. He was like he likes it and it's another way for men to Cum and he wants our sex to be more exciting because he's a freak. Idk what to do I love being with him and the sex is awesome. Please help me!!!!??