...someone that already have been married or/and have children? Especially if you yourself never have experienced neither? Would you be fine with this, or would you think that it would never be as special to him/her because they've already been through it? Therefore you wouldn't feel ok with it either. Or initially it doesn't matter, but it depends on when/why they broke it off, how old the children are, how involved they are, how old you are etc?