With love, you can make this work. My husband is not a vegetarian either. If I'm the one doing the cooking, he eats what I cook, or starves. You're bound to meet a vegetarian or two. As for your fiancee, I say just let him learn about vegetarianiam from your example.
People become vegetarian for lots of different reasons.
Maybe he will be more swayed by health or environmental benefits that the ethical animal rights issues. Just respect any efforts your finacee makes to reduce his meat consumption. In time, you will find a nice veggie niche for yourself. There are just too many of us out here for you not to find some more vegetarians to hang with. My fiance only last week decided to try the vegetarian ways of life.