Be a stronger person

I’m getting there on this one I think. Now that I’ve started my own business I’m having to deal with people wanting things for free or trying to get away without paying etc. I’m in the deep end here dealing with experienced businessmen trying to argue. I’m coping to an extent but I still need to be stronger.
Away from business, I recently told my ex that there is little chance of us getting back together. She’s been hanging on, hoping, (she broke up with me but changed her mind a little too late) and I didn’t want to hurt her but I’ve done it and I think that took a stronger person than I was a few months ago.