(TL;DR: My partner is having cold feet about TTC and I just found out I'm pregnant, he doesn't know yet)

So recently my partner has been showing aigns of having cold feet about having a baby. We had started the whole "if it happens, it happens/if it doesn't, it doesn't" kind of TTC with a little more enthusiasm toward the "if it happens" part. The past few weeks my partner has been going back and forth between "omg that baby is SO CUTE!" and giving me puppy eyes and "idk if I'm really ready for that yet". I've told him multiple times that if hes not ready then its fine and we can use condoms but he always tells me "no its okay". Well to add on to it I just found out im pregnant and he doesnt know yet. I'm honeslty so scared to tell him because I'm not sure how he'll react. What should I do? I mean obviously I have to tell him at some point but how do I bring it up?