Have you ever not wanted to have sex...

Yeah, quite a few times, my ex was addicted to it I think, not that I didn't want to have sex all the time but back then I was working 10 to 12 hours a day and I would be tired and just needing to get some rest, actually had to fake going to sleep. But I always knew that I would wake up to a blowjob and get all that I wanted the next morning. I miss that woman

Sometimes you do it as an investment in the relationship. If you love and trust the other person, the occasional mail-in bonk is really no hardship.

Mail in bonk, Headbang, I like that!

I've done it for the same three reasons and also the end-of-a-relationship fuck, which I could have easily done without. It just seemed more dignified to do it and get it over with than cause a big scene, which would have honestly taken more out of me.