Responses
Is it this one?
http://www.mangago.zone/read-manga/i_became_the_hero_s_mom/
Seems like "Everything was a mistake" not really sure though (￣ε(#￣)Σ
I believe this is currently being updated but it's about a reincarnated isekai fl who is obsessed with the son of the person she later ends up marrying- like to the point where she somewhat stalks the son and sends him gifts (I think the son might be a future villain?)
I remember a couple more parts so if you need more to think of the title... ヾ(❀╹◡╹)ﾉ~