LGBT: How frequent is it for someone to remain with their first boyfriend/girlfriend for their whole life?

Almost 17 years for us and I'm the first girlfriend :) Although for me it's my 3rd. And yup, we're still together and doing great! We love each other a lot and are closer now than we have been in a really long time. I foresee a really long term relationship/marriage here! (Married almost 10 years now).