It's a secret, and secrets are never a good thing.
As said though, you aren't burying your head in the sand, or carrying on as you did with your ex, so it is a past problem, so to speak.
Tell them. Even though you don't want help, they may be able to, and, should the worst come to the worst and they don't react how you would like, then better now maybe than down the road.
Me, I'd be happy that you finally told me, and consider it special that you felt you could.
PS, we all have baggage of one sort or another when we move on.