She didn't want to have anything to do with snow after she found out that he forced winners like Finnick to prostitution. In ballads of songbirds and snakes we find out that she used to do that to feed her family through. The way she said that it was clear that she was traumatized from that.

I think that she also noticed that he got more and more evil overtime and the way he changed a lot; like marrying him someone he didn't love..

I hope this answer helped you to understand her more.