Hi Millicent, and welcome to the forum.
When my Mom passed very suddenly, my Dad gave me all her jewelry (only child here), including their wedding bands and Mom's engagement diamond. DH and I used their bands when we got married, and since my engagement ring is a oval cut sapphire, I can't wear it on the same finger as the band. As a result, I wear the sapphire on my right hand and Mom's ring with my wedding band (at least when water weight will allow).
Since you don't want to discourage any prospective dates, have you thought about putting the ring on a simple chain? That way, you don't have to have it modified, and can wear it on your hand at a later date. I had to do this with my Mom's Claddaugh ring, as it is too small for my fingers.
On a side note, I am sorry to hear about your Mom, I know how hard that is. You may get upset by looking at it now, but one day you will be able to wear her ring with pride and a fond remembrance of her.