My husband wants to try pegging

I know it’s 2020 and our culture is much more accepting now a day’s but please don’t judge me for how I feel. My husband and I have been married for 3 years now and our sex life has definitely been waning, sometimes it feels like he’s just not interested in sex and then when we do have sex it’s pretty lack luster from my perspective . We’ve been taking about trying to spice things up and he’s brought up wanting to try butt stuff, pegging in particular. We’ve done smaller butt stuff (because he wanted to but I wasn’t really into it) before but never to that extent. I want to be understanding and accepting and do things that turn him on and make him feel good and maybe I just need to try it first (who knows I may be okay or even enjoy it) but to be completely honest the thought of it makes me feel gross. Has anyone else experienced this or have any advice that will help me navigate this?