I love my son's penis

My ex husband left me for a co worker and I became a little depressed. Then I walked in on my 20 year old son masturbating. David has always been shy around people and kept to himself. It was a shock seeing him cock in hand, but it soon passed as I registered the size of his penis. It was 11 inches long and a good 3 inches across, I couldn't believe what I saw at first. David tried to hide it from me, but I convinced him him to left me see it. As I touched it I got wetter and wetter and I had to try it. I convinced David to fuck me and that was the start of our sleeping together regularly. David is my third and youngest child and is the only one still living at home. I'm slowly getting him to ask me for sex, instead of me asking all the time.