How do you feel about this?

So back in 2016, one of my friends and I made a promise to each other that in August 2020, him and I would have sex. Now that August is approaching, it just popped into my head. I’m currently in a relationship and still expect to be in this relationship for a very long time so I won’t do it because that’s cheating.

Has anybody made a promise like this with someone and actually went through with it?