What to do to make anal more tolerable?

Hubby asks almost daily. Ever tried a few times and it’s been excruciating for me. Even after we get past the initial pain into less pain, it’s still not enjoyable for me, the sensation. Just feels like I need to go to the bathroom.

But he really enjoys it and I’d like to be able to tolerate it for him, if not enjoy it..

We’ve tried lube, and using a butt plug to stretch it slowly...

Any other tips to help me out?