I do too, healingme4me.

TMIML (fiance now ) & I have a very similr situation: Grandmother's ring is now on my hand. Her oringinal wedding & engagement rings & the eternity ring Grandpa Dale gave her for (I think) 2oth anniv. all got very worn and eventually the wedding band wore thru. So she & the MIL-2-b ( who is an only child) looked at every setting in every jewelry store they came accross for one that Grandmother E liked ( and Eleanor was a VERY opinionated lady, just a weeee bit hard to suit lol -- R.I.P) literally from NYC to Chicago to Phoenix to San Diego. heh. Finally somewhere in Iowa (i think) they found one that would accommodate all the stones, and Eleanor had all reset into one new ring.

She willed it to Crazyman, my fiance. AT THE TIME, he was with someone else & had been for a longish time. She was imo a true people-user, but w/e. When Crazyman showed her the ring, she ws horrified and wanted to pull it all apart, re-configure it into something that was her taste (which btw was trashy bordering on execrable, jsyk). YIKES! TO his huge credit, he recoiled and took the ring to his Mom's where it reposed in his parents' safe ever since -- till after he & I got together.

Here's what he & Mom decided: I kinda hated that old g/f had been offered Grandma Eleanor's ring, tho I didn't say so, he & Mom could both tell. Aw bless; what they did was take it to their jeweler, and he bought a new center stone, a diamond to be "ours", while still retaining the ring, the setting , the other stones, & the sentiment. Mom had the old center diamond made into a lovely delicate pendant, thus retaining her parents' engagement diamond/sentiment as well. Win- Win!

So that;s my (long-winded) tale of The Family Ring. Dunno if something like that would be feasible for you & your fiance? Or a different modification? Just a thought.
xo
Chyia Oh and, P.S. "Crazyman" is one of my fiance's irl nicknames, since jr hi. It's affectionately meant(mostly, heh)