My dad caught me masturbating

I posted in another sub and they removed it due to the fact it involved my dad, even though he was just a character not the issue. So I hope this is ok here.

I recently had a breakup of 6 years. He introduced me to a lot of things and made me crave sexual gratification. Since the breakup and my depression, I've been masturbating a lot. Like a lot. I masturbate at work and when I get home. I hardly see my dad, whose house I moved back into (my childhood home) and so I forget sometimes that he's there. I noticed last week that he likes to have the volume loud when he watches TV or listen to music, which isn't bad but sometimes it's distracting, so I've been using headphones. Last week, I was in a position, going at it, legs spread and I see movement and see my dad closing my door quickly. I was so ashamed. I wanted to ignore it but I worked up the courage to get dressed and go talk to him.

I stood there in the family room as he turned down the volume of the TV. I told him I was sorry for what he saw and he said that it was ok, that it reminded him of when I was younger. I was shocked and asked him what he was talking about and he said when I was younger and used to masturbate all the time and wouldn't stop. I have no memories of that. He said that my mom and him made an agreement with me that I could masturbate in my room but not in public. It lasted about a year but I don't remember that at all. He didn't want me to feel embarrassed and said that we all masturbate. I thanked him and told him I'd be more careful and maybe we should put a lock on my door and he agreed. He then said that maybe I could start by "Closing the door". I blushed and said I forgot and he said it wasn't the first time. I'm so ashamed. I don't remember the door being open, though I don't remember closing it.

All I know is that my dad has seen me masturbating and now is trying to normalize it so I don't feel bad. It's so strange.