I married my high school sweetheart when he was a one striper. Not much money, but much love! He bought me a lovely ring, the best he could afford, later on we traded up. You can do that at some jewelry stores, no matter how long it's been. Make sure what their policy is on lost diamonds. Mine, if you kept up with their inspection schedule, it was 100% replaced. I had my diamond remounted. My original ring was melted down right before my eyes and the gold made into a pendant. Over the years I've had to refuse diamonds! What was I thinking?! Lol. Nah, I know he loves me and I love the diamonds I have. And I would recommend looking for the ring together and deciding together what your budget will be. Thats what we did! 
Best wishes to you both.