Is it appropriate to ask him to pay towards daycare?

We aren't together but my sons dad has offered in the past to pay for stuff but in all honesty I've said no simply because I'm capable of providing for him.

Anyways. We don't have hard feelings (except for the odd time but it's always very minor, lasts a minute and we grow up and move on)

Would it be wrong to ask him to contribute to daycare? He doesn't pay child support (I'm not down for the whole court crap!) And we don't fight about our son. I just have him all the time it's never been questioned. He spends time but never like a week at a time.

Daycare is $1700 per month. Would it be ok to ask for some help for that? The worst he can say is no. (But he's not like that I know he won't say no)

If so, how much should I ask him to pay for?

(What's running through my head is that I pay for everything like diapers and formula and everything so I don't think it would be super wrong to ask for a little more than 50%....for example maybe $850 a month?)