My wife started out a vegan, but was very "do whatever you want" about it. Over the years she's started eating fish, eggs, and cheese, so that's made everything way easier. That being said, its never been a problem with us at all, but she's also been totally cool with not pushing it. I would say 30% of the time she cooks dishes with fake meat in them (which myself and the kids don't mind), and 70% of the time she cooks all the vegetables for a dish, and then splits it in half, putting chicken or beef in ours, and tofu in hers. Again, she's super cool about the whole thing.
Her brother and his wife are fucking cunts about it though, living with either of them would be a nightmare. We went to visit them and I brought donuts for everyone in the morning, I also bought a 6 pack of local beer for the evening. Her husband pulled me aside 5 minutes into the visit and told me they don't allow animal products in their house, and could I please take the donuts outside. I thought he was joking, but he was serious. So, I took the donuts outside to his porch, and proceeded to just start eating donuts. 20ish minutes later he steps out onto the porch with the beer and tells me that his wife noticed their was honey in the beer so it has to go too. I literally laughed in his face and said "Looks like my little donut party just got a lot more interesting!". I proceeded to get drunk and eat like 8 or 9 donuts out there. We were supposed to stay with them for 4 nights, I went ahead and got a hotel room and we left the next day. Their house was a fucking nightmare anyway as their dogs and cats pissed on the furniture and since they didn't believe in using poison there was fucking ants and roaches in the place.
Man they are the fucking worst. They genuinely wear "Social Justice Warrior" shirts and shit too. Totally insufferable.