I don't know, but I'm pretty sure when Natasha comes over she and Laura have hot sex that Clint does or does not join in on but certainly approves of, and she considers Natasha a second mother to her children because they are all a family together, and the way she and Clint are both convinced of this makes Natasha believe she doesn't have to have biological children to be a parent. And sometimes when Natasha has downtime she and Laura go off on adventures together that involve less danger than Natasha's missions but a lot more fun.

(Seriously, part of me really wants to write this poly family as a way to fix what the movie does to Natasha and the way that's juxtaposes with Clint's family life.)