Should I divorce?

I've been married almost 18 years, and my daughter is off to college in the fall. My wife is pretty, responsible and faithful. The problem is that we hardly ever have sex, maybe once a month. She usually rejects my advances, requests and attentions. I have to admit I prefer someone who has a little bit of masochistic tendencies, and she just hates that kind of stuff (didn't before we were married!). It's a source of never-ending frustration. If it weren't for my daughter, I would've left after a year or two. Another problem - I earn over six figures, and she prefers to be a singer/pianist and only earns about 15k per year -not enough to live on. She does make dinner and do the laundry and housework, which is no small thing. I've distracted myself with work, school and hobbies over the years, but I long for woman who shares my "kink" and whom I have a better rapport with. I'm 50 now and it's really it's kind of like now or never!