Of course you must get him to chip in!
It's his baby after all!
Paying for it is not an option for him; it is a responsibility.
Regardless of his financial condition, he's got you in this situation, so he should bear all the consequences, be it he's sticking with you/not the child still exist and it need to be supported.
True love endures through pain, if only a few tantrum from you scares him away already, then he's definitely not worthy of you
Well, that's my stand if i were you