How long is too long?

Let me start by saying I never want to put pressure on my boyfriend when it comes to getting engaged but when do I get to become “concerned”?

We talk about it a lot, he says he wants to marry me but wants to do it right... well we’re going on 4 years and nothing has happened yet. He wants to be able to afford a good ring... but I’ve told him multiple times I DONT CARE ABOUT THE SIZE OF THE RING.

I feel like my head is getting filled with these possibilities but months and months keep passing and nothing.

I want someone to want to marry me and not care of the size of the ring. They want to marry me because they want me.

I feel bad for thinking and feeling this way. Is that wrong?

Side story; we’ve been trying to get pregnant for 2 years now after we found out it was going to be nearly impossible for me to get pregnant. We’ve even tried IVF. So ends are tight, I get it. But it’s not about the cost of the ring, it’s the meaning behind it. Just seems like an excuse at this point and I feel myself getting tired... defeated :( I can’t have a kid nor does the man I’m with want to marry me anytime soon apparently.

I don’t know what to do.