I grew up with a fence and had one in our first couple of homes. We moved to Minnesota and most people in our area didn’t have fences. We put in an electric fence for keeping the dog in. We came to prefer the open landscape. We moved back to Washington where fences are more common but if a neighbor wanted to split a fence I’d think long and hard because I’m ok without a fence because I prefer the openness. If I had a pool I would fence it. Just because one neighbor wants something I don’t want doesn’t make me responsible for putting in money. I would however offer to help work alongside him and build the fence.