It's likely a lot more than you think, after all it's the showbiz industry..
(Why do I keep seeing you everywhere I go????)
lol i guess we read similar stuff
there was a plot in 30 rock about it lol, but i imagine some do get together if only it's because "well we see each other everyday for this series" so it naturally happened, tho i imagine going all the way to a fancy wedding would def be quite something. versus actually legitimately having kids together and stuff, not that divorces can't still happen despite it (tho some nepo hires aside must suck for some kids who wanna live relatively 'normal' or so otherwise. like maybe some kinda private school or so like "My parents are celebs but i don't also wanna act/ be in the spotlight but just my last name gets attention from ppl" or so), if not a celeb adopting foreign babies too but yeah i don't rly follow pop culture stuff other than something you eventually hear about and briefly see on magazine covers even if you don't go outta your way to keep up
tho i imagine ppl avoid it in Jp/korea b/c of the 'idol culture' stuff versus them having the 'pretty boy' rockstars bait the fangirl by flirting with each other lol