Engagement Ring -- need opinion on this?

My boyfriend, now fiancee, proposed to me a few weeks ago. He gave me a soldered heirloom ring (the engagement ring is basically welded to the wedding band). I’ve never been knowledgeable about the etiquette of wearing rings, but I’m not sure how appropriate it is to wear the band with the ring. He’s suggested to separate them but I’m worried separating would decrease the value of the ring. And also, it looks very nice together. My only issue is that I am basically wearing my wedding band with my engagement ring, and I’m not sure with regards to ring-wearing etiquette how that stands since we’re not married yet.

I’d appreciate some feedback from people, maybe some of their own experiences or friends’ and family.