Partner and female co worker

It seems like they're playing mindgames, and making you out to be paranoid and insecure. They both sound horrible. For your own sanity, walk away.

I understand why you feel the way you do based on your previous experience.

But controlling your partners friendships is really unhealthy.

You either trust him or you don't and if you don't the relationship is doomed.

This relationship is dead in the water now. I couldn’t be arsed with policing my bloke’s behaviour and worrying about who he’s seeing. No trust = no relationship for me. Time to throw him back.

He is slimy lying bastard. Get rid.

My dp has women pals who are colleagues and they've come for dinner, pop in for a coffee, they've visited us when our babies were tiny for baby cuddles.
They've equally met up for lunch alone many times. Before he's gone I've said "send my love to sally" because its never once been a secret. And never once have I felt that dread in my belly I'm being cheated on.

Your partners secrecy is the red flag. If he's lying he's preparing to cheat.
Get rid and do not let him gaslight you that you're paranoid or unreasonable. He is a snake.
Walk away head held high you didn't put up with his twattishness.

She thinks “you’re crazy” becasue that is the picture he has painted. He should have your back.
but also if I was friends with a guy, unless I thought there was abuse, I would back away from the friendship if it was upsetting his gf/partner.

You aren’t anxious or hysterical, you are picking up on it sooner than a lot of women would purely because you have been burnt before.
He will accuse you of being anxious, uncool, etc right now because nothing physical has taken place. Yet.

I think going slightly against the grain that there is room for a bit more nuance here. In a long term relationship people are bound to go through crushes … it’s normal. it’s how they manage them and obviously whether they act on them which counts. I would firmly maintain the boundary of no outside work contact to give your partner a chance to control that crush and for it to run its course. If he continues to push the boundaries and to fib to you then of course you can’t put up with that.

I don’t think you’re unreasonable. It sounds like an affair in the making tbh. Really he needs to change jobs. If he can’t see this creeping into your lives or is letting it in that’s a big issue. X

So when they were messaging over team can I presume her asking how tall he was is because they had not actually met in person?

It's practically internet dating, and then they meet up - trust your instincts, something is brewing here, whether he wants to admit it or not

A friendship? Fine

Nonsense about having a "connection " and meeting up for secret walks? Absolutely not.

I'm quite laid back about stuff but this would have me reacting the same way. Sending selfies to each other too seems weird too. I wonder how he would feel if you were sending pictures to a younger male work colleague and meeting them behind his back. I think women have a good intuition about other women's intentions in situations like this, where men can be a bit dense. 🙈 I hope that you are OK.

You are absolutely not unreasonable. That woman is after your partner. And he is clearly interested as why would he pursue this knowing you are uncomfortable about it. I would leave him before he leaves you for her. They have probably already been intimate most likely. Especially meeting up behind your back while you were out the country.

Hmmm walking into it eyes wide open

The man is so audacious that he's trying to date a new bird under wife's nose!
And imo the work colleague is brazenly pursuing your H. What sort of woman finds out that the friendship is making the wife uncomfortable and instead of backing off, comes over for a "walk" when the wife is away???
I've had work friendships over the years. It's just not on.

Not at all hysterical OP. He’s either sleep walking into an affair or dipping his toe in the water to see if things move along.

Make plans to split- no trust, no relationship!

The damage is already done in my opinion. He's dishonest and I think history is repeating itself.

Personally I think you can only control who he is friends with if you're willing to have him control who you're friends with. It's not healthy for you or your relationship to be on edge about every connection he has nor him you, if there's no trust in relationship there is no relationship.
If he's going to have an affair and leave you for someone else he'll do it regardless of how many times you stop him talking to women.
And I say this as someone who's exh did what your ex did.

Completely missing the point of the thread, and apologies to the OP, but have realised I am Mavis. I love wordle and Ludwig. It’s nice to know that I am not considered a threat to anyone’s relationship (I’m really not)

And don’t be surprised if when they do get together, and it sounds inevitable, that he’s all
’but nothing happened until after you broke up
with me’ 🙄
how dumb do these men think we are?!

I agree with @NachoChip, he's weighing up his options whilst maintaining 'we're just friends' if you question it. Men rarely leave unless they have someone new lined up and this sounds like the 'transition' phase.

Right now they are "friends" so he can claim they're not doing anything wrong. But where they actually are is in the "getting to know you" phase and exploring their connection, as evidenced by conversations between them that have crossed boundaries and doing what they can to meet up without you/your knowledge.
Anyone can meet someone in life where there's that "if I wasn't with my partner" feeling but it's how he handles it that matters. The right thing to do is to steer clear. Maybe he hasn't thought this through and is just doing what he feels like without considering the consequences. Tell him that....it doesn't have to be an ultimatum, more that if he chooses to continue this "friendship", that to you his him exploring his options and message received.
I'm sorry OP, I hope he makes the right choice.

OP I'm also a "cool wife" by Mumsnet standards. My partner and I have platonic friends of the opposite sex we sometimes spend time with alone. I sometimes eyeroll at some of the posts I see on Mumsnet around the panic of an opposite sex friendship.

This is not what you're describing at all imo. The lying, the telling you you're crazy, the keeping you from meeting, the waiting until you're gone to meet up behind your back, the lack of respect for you and your relationship. All crazy red flags. No one does these things for a "friend". Your partner sounds like a first class idiot.

My husband and I don't share many friends.

Most of my friends are through work. We text evenings and weekends, share holiday photos and socialise regularly. We don't bring partners.

It's just different strokes.