Hetero couple, they are married and have children already. But at one point the mother gets amnesia and forgets that she is married and had children, so the father tries to get her to fall in love with him and their children.

I don't know if there is any with this plot, but i got the idea from here : [url=]https://www.mangaupdates.com/series/ha41402/a-child-who-looks-like-me[/url]

That's actually the current arc of Ojii-san to Obaa-san ga Wakigaetta Hanashi so like ch 88 or something

that's a good recommendation , but i would prefer a younger couple. still, thank you.