To tell her the truth?

This is a fair point.

I still don't see the harm in answering the question though..

I just don't see why it's such a big deal having casually dated someone in the past.

His new gf could be lying about having asked him about sleeping with OP. I'd ignore the message OP, it's a situation that whatever you do will be tge wring thing. Don't get involved.

You know, if you're going to reply to a post, it's probably a good idea to read it first.

You've had people saying it's not for you to get involved in their relationship except that she has chosen to involve you because she wants the truth and she's not getting it from him.

And, no, your sexual history isn't anyone else's business but I don't think it's revealing your sexual history to confirm you dated someone casually for a bit but it was no more serious than that.

She clearly suspects that he's not being honest with her. And she's right because he's outright lied to her.

it's not messing with their relationship to tell the truth

He has created this situation by lying to her and, tbh, the older I get, the more I think my loyalty lies with a woman who has asked a question wanting a truthful answer than the man who has lied to her and put her in that position.

I'd tell her the truth.

Personally I’d tell the truth.

Message her back and just say “are you okay?”

It's in the first OP message. "She’s just sent me a message saying that she had a feeling we’d had history, but he’d denied it, and to please tell her the truth."

How do you know he's denying it? The new partner may not have spoken to him about it.

Thinking about it more I would not respond to her. At all. I did originally say tell the ex and tell her the truth.

But no, who the hell knows what craziness that might stir up?

Send her message to the ex and say deal with this, after you have told your husband about it, because secret messages to your ex may cause dramas too.

Then just bow out entirely. Don't respond to either of them on the subject at all.

You refusing to lie is causing nothing, your ex has caused these issues by lying. So weird. Maybe he just still really fancies you and it was obvious to her and he lied in panic?

Whatever his reasons, you're not his shield and you should try to extricate yourself quietly from their drama.

I wonder what's made her think that? How are you acting towards each other?

We briefly dated is more than enough if you want to reply. I suspect she will be off with you or stop speaking if she’s demanding to know info.

She doesnt have the right to ask you that. You need to redirect her to her partner.

I wouldn't get involved, she could be a bit batshit about her blokes being friendly with ex's and there might be a reason he hasn't told her.

Not your circus

This

Why on earth would you write all that. It's no big deal. He's weirdly making it a big deal.

This. And I would add do not respond, at all to her message.

If the OP is ok with lying, that's her choice. But if she chooses to tell the truth, it's his lie that will have caused the hurt.

Tell her sorry you’re not getting involved in their relationship issues. Then ignore any further questions. If she persists, tell her partner to grow up and tell her the truth.

Awkward situation for you op. I’d go with @LivingLaVidaBabyShower response.

Your sexual history is none of her business but him lying about it is making it a bigger deal. There are obviously issues in their relationship. Not your problem.
Send him a copy of the message and tell him to deal with it as you don't want to be involved.

Same. It's not great that he lied bit maybe she's a very jealous person.

So you're "(genuinely) thrilled for him" and " really really like this lady", but nonetheless are considering doing something that you know will hurt both of them?

People lie about trivial things including sexual encounters all the time. Just deny it and forget about it.

Tell her and go for a rewrite of what you've already said.

I was shocked when you messaged. I'll preface this by saying I really like and respect you and i absolutely do not want to cause you any hurt or create any discord between you,
We do have some history (we were on and off for 2 years) although it was never serious. Certainly there is nothing romantic between us now as I'm very happy.with X and as far as i can l see you are the love of his life.

I really hope you can talk this through with him and this doesn’t affect our relationship, you are a wonderful person and while I'm really not sure why he lied, if i had to speculate it was perhaps a fear of losing you?

I'd tell your partner so hes aware and sent idiot ex a courtesy text. "Y messaged me and asked about our past. I have replied honestly and factually."

WHAT was he thinking? Why lie??? 🙈🙈🙈

And you have absoluely no reason at all to make yourself a liar for his sake. If something comes about because of his lie, that's on him, not you. Best if you could just completely ignore her and not respond at all, but if that might cause issues I would discuss with your husband, message the ex and tell him what she has asked, ask the ex to tell her and say that if she asks you face to face you won't be able to lie about it.

I wonder why on earth he lied. Big mistake.

If it happened over the course of 2 years, I’d tell her without second thought. Surely if you lie then you risk someone else dropping you in it further down the lie, and she’ll then wonder why you didn’t tell the truth?