Not exactly body swap
Protagonist's wife wants a divorce with him right after the birth of their child, he's got no idea why she wants this until he woke up the next day in her body, 9 months prior when she just gotten pregnant. Now reliving their lives but this time from his wife's perspective, he slowly learns and realizes how much of a jerkass he was towards her (now towards himself) during her pregnancy.
This looks… very interesting
It's not, really. It's a very simple short duojin about a prince who drinks a potion he confiscates from a street rat that turns him into a very horny girl.