How to clean between ejaculations?

I have been using a combination pill for 6 cycles now. Initially everything was going great. Into the 4th cycle I started to get really moody with irratic behavior and mixed feeligs (extreme jealousy, irritability, mood swings)- basically I didn't feel like myself. After some research, I decided to go off the pill. For protection, we are going for condoms and the pull out method. However, I am concerned about sperm being present from pre-cum or the previous ejaculation. How can I make sure that no sperm is present other than peeing in between?

Thanks!