Female as substantial bearer of risk, is in control
Vasectomy is more than 99% effective at preventing pregnancy.
Anchor point, rope, rockface, falling.
https://youtu.be/1pancZunspo?t=72 https://www.musixmatch.com/lyrics/Dan-Sultan/Seeds-That-You-...
I can't imagine my long term partner, now fiancee, wouldn't trust me with something so important to us both. Why even be in a relationship at this point.
(pregnancy is one, sure, but there's also things like blowing half your yearly salary on a sports car on a whim)