Do I need to tell my ex I briefly dated someone he knows?

[YourBluntGuide]

Hi everyone, i could do with some advice.

So me and my ex broke up a little over a year ago.

He had a new relationship, and i was seeing a guy for about 2 months. I later found out my ex and new guy know each other, not friends, but id say family friends.
Me and the ex are now trying again, it feels a lot different this time. Do i need to tell him about the fling. I know it sounds like the best thing to do, but it's just going to hurt him and it really was nothing other than a mistake!

If there's a chance he'll find out you're probably better off mentioning it, you haven't done anything wrong

Exactly as @MyMilchick says plus he can't moan as he also had a previous relationship

If you think he's going to be upset, I would just tell him, you were split up at the time and he was with someone else.

Nothing to do with the ex / new partner you wernt together you both dated other people its no big deal

You could say, "Well you remember when you were off having a relationship with X? Y and I went out a couple of times." What can he say?

I would want to know if I was in that situation.
Would rather be told by my partner in advance, then later find out via someone else or worse the person you had the fling with.

If you were in his position, how would you feel about finding out from a friend after the fact?

When did you find out they knew each other? After you ended it?

We were on a break!

Yes, mention it.

Yes you should let him know
no it’s not really anything to do with him and no he can’t have any complaints or issues, but it’s a reasonable piece of info to pass on tbh

Yes, transparancy is always favourable, imo

Yes, tell him! Surely if it causes trouble that’s a red flag for hypocrisy and you’d want to know about it?

May I say, this ain't going to end well.

You know when you were with Jenny, I had a fling with Adam Roberts, just in case that ever comes up in conversation.

If he can't cope with hearing that, and you're dancing around wondering how to tell him, because he will be jealous hurt, then I would call off the reconciliation right now. You haven't made a mistake, you carried on with your life without him. That's perfectly reasonable adult behaviour.

As you are trying again then yes I'd say something as best it comes from you rather than finding out from the other guy or someone else. Transparency is always best.

Just casually say something like "Oh you know your friend X, he's hung like a donkey". If he wants more information he can always ask.

He can't really get pissy with you as he was in a whole new relationship whilst you only briefly dated this guy maybe a couple of times. You've already pointed out they're not best friends they know one another through a family friendship connection.its not as if you shagged his brother