My(27F) bf(28M) gave me a prerequisite when I proposed him.

I've been together with my bf for the past 5 years and he is a sweetheart. We moved in together after 2 years and things have been great I love him a lot and I know he loves me too. I work in a law firm and my bf is a physicist and works in one of the best institutions in the country for his field. So he recently got tenure and I'm doing good in my field too. We live! in an apartment we bought together.

Recently I've been thinking about marriage and didn't just know when the right time was so day before yesterday I just popped the question, he was just so happy and obviously agreed. Mind you this was done in our home in a private setting. When the initial excitement started to wear off I could see he was visibly distressed and right before the bed he asked me " will you want to have kids with me when we get married?" I said yes. To which he replied "Then i can marry you only if you agree to give me absolute control over our child's academics. We can share all the rest of the stuff and I even agree in advance if you would like reserve something solely you two but i can't compromise on this. " I was absolutely gutted as I didn't know what to say. It was so out of character for him. I said that I think that both of us should be involved in every aspect of our child's life he just said no. I tried asking if something happened but he just left for the couch. I took the day off as I'm not in the right state of mind rn. This morning he entered the room, I was awake but pretended to be asleep. He just kissed my forehead and when he left I could hear him sobbing. I know something has happened and most probably it isn't even related to us. I tried contacting him but he hasn't returned any of my messages. I asked him if he would like to have lunch about an hour ago and he just replied no again. I don't know how to proceed or what to make of my relationship anymore.

How should I proceed?

TLDR: I proposed to my bf of 5 years and he laid a condition that he wants absolute control over our future child's education when we conceive in the future and is trying to dodge my attempts to talk ever since.

EDIT: A lot of comments are asking me for more info but I'm just are oblivious as you all are. He is coming home in about half an hour. I'll talk to him and update again