Dear Mary Jane,
These past fifteen years have been phenomenal, but now I think it's time for me to move on. I know you are upset, but I think it's just best for what is going on right now.
You've lost your luster. You've become lazy and fat. You're hard to work with and you take up MY side of the bed. I have to resort to either sleeping under you or on the floor, seeing as the dog has the couch.
You've begun to age quicker than you should have. You are only 38 years old and already, you are quickly wrinkling and your hair is greying. If you include your freshly grown mustache, you look just like your mother.
I'm not going to mince words here, darling. I've just...found someone else. This person suits my needs better than you ever could and is WAY more attractive than you. This person is SO much better in sex than you are and I don't have to worry about them getting pregnant. They can't.
P.S. To put it simple, I'm gay.