Am I wrong for feeling uneasy being friends with someone who cheats in their own relationship?

My partners friends (not best friends, but have tried in the past to as they put it “team up and become the power couples”, we obviously weren’t interested and they played it off as a joke. They constantly excuse each other’s behaviours, hers being cheating on him with his work friends and his being getting so disgustingly drunk he ends up naked and covered in spew and touches people inappropriately.

I feel terrible that I have this feeling of distrust and unloyalty whenever I’m with them when they havnt given me a reason not to trust them personally but I can’t shake that they find this acceptable behaviour towards other people, what’s stopping them from being disloyal to me if the time ever arose? Am I over thinking this?

I always trust my gut but don’t want to cause a divide between myself and partner.