Sleeping with somebody you call your dad is a curse to you. Imagine getting a child with someone you are calling a father? A man who has slept with your mother? Why do you want to break her heart? This man could be having other affairs outside and could infect you even with HIV. And that liking and favouritism she has for your sister will increase ten times when she finds out. Suppose it was you whose daughter was sleeping with your husband? How would you feel? What would you do to your daughter? That very answer is what your mother will do when she finds out about this. However, be in the know that you are looking at the wrong man. I think you are looking for a sugar daddy to spoil you by giving you money and other things.