Asa Okitara Tsuma ni Natte Ninshin shiteita Ore no Report

The main character Yuuichi suddenly faces a divorce when his wife Hana says "It's impossible to raise a child with you," but he doesn't understand why she would say this. When Yuuichi wakes up after hitting his head and losing consciousness, he finds himself in the body of Hana near the start of the pregnancy—he will relive his past behaviors from the perspective of his wife.

(Source: Chibi Manga)