Anal is Getting Too Tight

My husband was the first one to introduce me to anal sex and it was amazing. But after this morning session he mentioned that over the last couple years (we’ve been together for 3) my ass has gotten tighter to the point it’s hard for him to finish.

Most of my top orgasms are from anal sex but now I’ll have 1 or 2 and then it’s like ‘just finish and get out’. I hate feeling that way with something I used to enjoy.

I got a butt plug and lube to help loosen me up but sometimes it’s hard for my muscles to relax and it hurts us both.

What are somethings I or we can do to make anal sex more comfortable again for the both of us?