Responses
The only one I remember where the mc ended up with the father-in-law (AND with the son) is this: https://www.mangago.me/read-manga/the_kang_s_yeesu/
It's been years since I last read it though so I have no idea if it's what you're talking about
Can someone recall this smut mang about a guy meeting his father in law and they end up taking a bath together scrubbing each others back and then fthe father in law f**** the guy, theres part twoo where they went to a vacation in bath house