Science is a step ahead of you, man.
10 year temporary vasectomy on the way. Google it (I'm at work and everything is tracked, don't want to have to explain this one). It essentially works by injecting a gel in some of the ol' tubes, preventing fertile ejaculation.
After about 10 years, it starts to wear off (I assume at the 7-10 year mark, you'll go for "check ups"). They injection can be renewed, and there's another injection which has a chemical which destroys the gel, if you wish to reverse the procedure early.
If you can face the idea of having a syringe stuck in your manjunk, this will be the obvious choice.







