You're clearly ambivalent and uncertain, so I would advise putting the bracelet in a drawer and not looking at it for several years. I've given away precious things because they had bad memories attached, then five or six years later wondered what had ever possessed me to do something so rash. Getting rid of the items had no effect on how long the bad memories persisted. After several years either the memories were still present or they were not, but either way they no longer had any association with the things I had given away. So I suggest putting the bracelet aside and forgetting about it. See how you feel about it in a few years.
In fact I suspect that the good memories of your son will eventually blot out the memories of your ex-husband and eventually you will just forget about him like all bad things are eventually forgotten. That's what the mind wants to do, forget all bad things. And then the bracelet will remind you only of your son. So tuck it aside until then.