A few years ago I jumped, head-first into veganism and never looked back. Upon informing my then-boyfriend, now-husband of my decision, his initial response was that he would go vegan too. My path took a sharp turn towards activism, while his path never really changed. I found a great core group of activists turned friends and I didn't mind that my husband wasn't involved. This was my thing, he was just along for the ride.
After about a year, his commitment began to waver as he grew bored with limited vegan options (limited only in that I'm a lazy "cook" and can survive solely on chips and guac). When he informed me that he wanted to go back to his previous diet, I wanted to die. Many fights ensued because I just couldn't understand how he lost his resolve, especially since he knew so much as veganism is pretty much the only thing I ever talk about. I was so ashamed and embarrassed that, despite making veganism my whole life, I couldn't manage to convince him. Things hit a turning point on our wedding day when I received a phone call from him while I was at a Petland demonstration (protesting their continued use of puppy mills, yes, just a few hours before I was to be wed) that he had gone out and purchased a silk tie. I almost called the wedding off over a silk tie. Sobbing, I turned to my fellow vegan friends and they were able to talk some sense into me and remind me that despite him not being in the same place as me, that he was a wonderful, respectful man.
From that point on I eased up on him and in turn, his only transgression is cheese. We keep a vegan home and he agrees that if we ever have children, they will be raised vegan. He even advocates a vegan diet to his friends and he's never disrespectful about the moral choice I've made. He knows it's the right choice, he's just not ready to make a full commitment and I have to respect him as he respects me. And I know that my constant, consistent message means that markedly less animals suffer because of my influence over him. I respect his decision because he respects mine.
I can't say things wouldn't be different if he made belittling comments or made a point to eat animals in front of me. A relationship is a partnership that needs to be built on respect and I have to question what kind of person doesn't respect the compassionate choices made by their partner. I do have a few friends who have experienced great struggles in their marriages because their new-found kindness seems to have given their spouses a license to be extra cruel, not just to the animals, but to the people to whom they made vows. At that point one may decide that they need to re-evaluate their relationship and if it's worth the heartache if that person doesn't seem to be able to at least be respectful after coming to terms with the new vegan "lifestyle."
That said, if I ever find myself single, I would never enter into a relationship with an omnivore. I just don't have the patience to go through this again.