You could have it enlarged floo, might mean adding some gold. I'm sorry you can't wear it any more as it is.
Being sentimental about jewellery is a funny thing. My mum lost her engagement ring, she thought she pulled it off when taking off her gloves in a department store. Her fingers had got a bit thinner so it wasn't as well fitted as it had been. She asked in the shop but no-one handed it in. She was really upset about it, for goodness knows how long. She bought herself a replacement ring but kept saying, "It's not the same". I felt sorry for her but after a while I thought, "You're fit and well, it's only a thing after all".
Some years ago we were burgled and my engagement ring was taken. I still feel a pang when I think of it, I too have replaced it but "it's not the same" and when I go out, I look in second hand jewellery shops in the hope of seeing it which isn't likely. So I understand a bit more now how my mum felt.