Should I have a baby with my ex? Thoughts?

Basically I want to use my ex as a sperm donor. I’m 32, I don’t want a relationship with anybody AT ALL but I have a very very strong desire for a child. I’m very well off financially and have an excellent career. My ex and I are on great terms, we don’t have any feelings for each other. I’ve talked to him about this, and he said he needs time to think it over. He knows that I would not *expect* him to have a relationship with the child or pay any sort of support, we’d have what’s essentially a contract in place stating this. Am I crazy for considering this? My other option would be to find an anonymous sperm donor and go that route, but this seem like a less complicated process. Thoughts?