I think one of the key reasons Dave doesn't ever want kids is because he couldn't even keep up with Leanna's energy and youthfulness, which wasn't even that high or anything because she was a lazy schlub in her own way, but DSP needs a day long nap after window shopping.
Kat by contrast seems like a very boring anti-dynamic person so they're perfect for each other that way. Imagine those two with a kid? They can't even deal with Jasper at bedtime and have to lock him in their room with them so he doesn't run around the house lmfao.
But yeah, Leanna probably went on a lot of trips and outings with The Guy with having fun being her number #1 priority, Kat by contrast seems more like The Guy and first considers what's in it for her specifically, and in some twisted way it makes sense she didn't wanna go to the muddy Pumpkin Patch place in her literally just purchased boots. Who buys brand new boots knowing they're going to be walking through mud all day?
That's what wellies are forDave, you fell for her grift.