butt stuff

i’ve been thinking about this for awhile, but pretty much my husband really likes doing butt stuff. i really don’t. the only time it ever really happens is when i’m on my period n superrrrr horny, otherwise i’m almost never in the mood for it. a little while ago he brought up experimenting with doing butt stuff on him, like little things like putting a finger in it when i suck his dick or even just rubbing it. he rarely ever asks for it n honestly i don’t really like doing it but i do it for him and i know it’s normal for guys to like stuff like that. but everytime we do stuff like that, immediately after he says he feels gross about it and regrets doing it. so lately whenever we’re doing stuff and he asks me to do it to him i tell him i don’t think it’s a good idea but he’ll beg me to do it so i do it anyways just for him to tell me he feels gross again after he finishes. he also asked me to lick down there before but that kinda grosses me out so i didn’t, sometimes i lick his taint when i’m sucking his dick tho and he really likes that. but ig my question is, is this normal ? like for him to feel so guilty and gross after we do those things ? does this happen to anybody else ?