I am a vegan male.
I dated a girl for 5 years that ate the flesh of beasts. ( I've been vegetarian 8 years, vegan 1)
Things were great with her - mostly. We had our minor problems, but nothing huge, we didn't fight much, our personalities matched evenly, things were pretty good most of the time. We were practically engaged.
But there were always certain things that caused me to doubt our future together. And several reasons we broke up. Namely, and one of the largest on my side, was that she isn't vegan. I know I want to raise my future children vegan, I want to live and love with a vegan. She obviously didn't.
There is only so long you can hope a person will change until you realize that you cannot expect people to change.
We broke up a year ago, and we still talk once a month for a couple hours. It was a mutual break, and we still care for each other as friends - no people really know us like we do each other - but we know it could never work out between us (there were things besides the veganism as well).
I didn't just lose my girlfriend, I lost my best friend.
I don't see myself dating a non-vegan girl again. Don't think I would like to sit next to someone I love on that level again while they indulge on the flesh of beasts.
Others could, and many do.
Blessings be with your relationships.