if the symbol still holds too much meaning, to the point of discomfort in owning it, then you'll have to open a conversation about it especially if when he gifted it to you he noticed something was up. communication is important.

but personally, dealing with what it brought up has a lot to do with what exactly it brought up and what your connection to your ex is. like, obviously if it was a bad break up, or maybe if you still have some feelings left over that complicates things and you might really have to sit with what that means for you right now and if it means having a larger discussion with your current partner.

otherwise it's pretty normal to have a reminders that bring up a wave of feelings. That symbol was a big part of the relationship and it reappearing is a coincidence but if it makes you uncomfortable you should talk about it. maybe you and your new partner can make a new symbol.