I don't like my mom's boyfriend and I don't know why

So my mom has been seeing this guy since like end of April, I don't really remember. They did move really fast into the relationship but this is probably the healthiest relationship my mom has been in, yet despite all that, I can't bring myself to like the guy. Dont get me wrong, hes really great. Hes very open and kind, and buys us treats, but everytime I hear him I get annoyed. His obnoxiously loud laugh is annoying, the way he plays his guitar is annoying. He also loves mansplaining a lot. The most annoying aspects has to be how much they suck each others faces off every chance they can get. In the kitchen, restaurant, mall. Worst of all is my bedroom is exactly next to my moms, and there's only a thin wall between us. I also can't handle the sound of kissing, it absolutely disgusts me and I don't mean it with how you find mold disgusting. Like literally my resentment grows a little at each smacking sound. Not to mention how God awful it sounds when I hear my mom whimper and gasp. Absolutely wretched. And maybe it's also cuz I have trust issues when it comes to older men, but something feels off for me and I don't know how to explain it.