hm, i think i'd be fine with contributing some money if there was a certain ring i wanted. of course my SO would have to be okay with it too.
my SO and i have done this with bday/xmas gifts before. some years there's nothing i really want, but i'm saving up for a bag, or a spendy pair of shoes, and he'll offer to split the cost with me or whatever. and it's fine, but honestly, a little less special and exciting than when he goes and surprises me with something on his own. so i'm not sure i'd go this route with an e-ring, but i don't think there's anything wrong with it.
my SO and i have done this with bday/xmas gifts before. some years there's nothing i really want, but i'm saving up for a bag, or a spendy pair of shoes, and he'll offer to split the cost with me or whatever. and it's fine, but honestly, a little less special and exciting than when he goes and surprises me with something on his own. so i'm not sure i'd go this route with an e-ring, but i don't think there's anything wrong with it.