He doesn’t want to get married..?

We have been together for almost 3 years, we have an apartment together and I’m about to give birth to our second child in 2 weeks. He proposed (in his room) and gave me a very expensive ring before we had our first child, I recently got him a ring on Valentine’s Day and brought up the marriage thing again.

We previously talked about it because when he gave me my ring he called it an engagement ring, but when his sister asked when we were getting married (not too long ago) he called it a promise ring and it made me very upset which he didn’t understand. I won’t go into that argument but I don’t see why he keeps putting it off or being weird about it when I bring it up, I told him if he doesn’t want to get married or not for a while to let me know so I understand and he told me he wants to but won’t go through with anything yet, he always says maybe another day

I don’t know if I’m wasting my time or what, we’re both loyal and everything’s good between us for the most part (we argue every now and then but get over it)

I just needed to rant, any advice would be appreciated