Does anyone else think bathroom etiquette is still important in a relationship?

So my fiancee 47 male and I 41 female have been together a yr abd half , I usually like to shower alone but he says he loves to shower with me, so most of the time we do. The problem is , every single time we do, I'll get in first, and he without fail takes a dump, while im.in there, and then he gets in. Recently after many hints that go unheard, I've decided to shower alone now,and he gets offended. Yesterday I point blank told him.it was rude and disrespectful to do that when someone is in the shower, he really didn't say much.. am.i Alone here, thinking it's just nasty to do that to someone while they are showering?