What would you do?

Someone wants to start a relationship with you but they dont want to completely cut ties with an ex?

So this actually happened to me and I walked away and decided to go no contact. They really begged me to stay and told me how much they didnt wanna lose me but no matter how much I'm in love with them and want it to work, I'm just not willing to negotiate on certain things. I will miss them terribly though😔