The issue we're discussing is whether we should use one of his grandmother's rings or if we should get a new one for our engagement.
He made a pro/con list for both.
Grandma's ring pros: free!, substantial stone size
Cons: Might not fit (explained to him that that is easily fixed) and that it might not be what I want (explained to him that I want whatever he wants to give me.
New ring pros: More modern and more selection
Cons: it isn't free.
My concern with this is that he didn't say that he wanted to pass down Nan's ring. I think that he's leaning towards that because she has more than he could afford. I think he puts more emphasis on the ring than I do.
This is what we agreed on: The ring is an important part, but it's not the most important and having one, not having one, having it be large or even really ugly is not going to change the fact that I will say yes. So we've decided that we will look at everything that we have selected and make an informed decision that way, instead of him feeling like he has to guess. By doing so, he will still have the ring at the proposal which is so important to him, but we also can make the decision together.
That is, when we're ready to be engaged, which we aren't yet, so this all can change.

ETA: The point of this post is that we hit another relationship milestone, a sirous conversation about this aspect of the engagement with compromise on both sides. It's a good feeling.