engagement ring, help!!!

July last year my boyfriend proposed to me! My ring is gorgeous and I love it! the only problem is it doesn't fit me any more☹ because of certain problems I have become depressed and kid of turned to food (no excuse I know) and now it doesn't fit as my fingers have got a bit chubby☹ I'm really gutted about this as I LOVE my ring. my boyfriend has said it's okay that it doesn't fit and I Will get it back on eventually but I know that secretly he is gutted. so basically I was thinking of buying myself a cheap but nice ring until I loose some weight. I was going to surprise him and hope that he loves it! Do you think it is a good idea or not? please helpp, thanks in advance!💓💓