Please, please let me find this, I am pretty sure I read this here
so, a girl and a man gets married, with another small girl telling the girls' husband that she will marry his wife after he died. Husband eventually died due to certain health issues, and the two girls slowly started dating and the small girl tries to help the elder girl to be happy again after the death of her husband.
The real question is she saying that because Momo asked her out first, or because she had to ask Momo out. I suppose it's a matter of opinion which is losing.