About to get my tubes tied

I’m about to get my tubes tied, I have no kids and want it to stay that way, but after signing the consent forms i got worried that my partner might want kids in the future even tho he said he doesnt and is 100% supportive of my choice. Im 100% sure that I do not want kids now or in the future but part of me is worried about my partner because he was seeing this girl who has a daughter when we weren’t together.

I’m just worried that he doesn’t want kids with me but would want kids with somebody else.