To feel uncomfortable with this message exchange

I'm sure if your partner tried to "shut it down" and forbid you from doing something you'd be on here complaining, but it's okay for OP to do that because.. She's a woman?

To be honest I would just wait and see how this plays out.

If you confront him now, he will 100% go to her for support and if they’re meeting up in person, it will be easier for them to cross a line if he is pissed off at you.

But ultimately if they do end up together there is absolutely nothing that you can do now to stop that. You can’t switch off the feelings they may have regardless of what you say/do. It almost reads like he thinks she’s the one who got away.

It does suck for you and it is horrible for you but there’s nothing you can do to control it, this is all on him now. I would just think about your exit plan just in case. Nothing may come of it, but you’ll feel more confident knowing you have protected yourself.

This is all wrong and you know it OP. It needs to stop.

He is (probably) trying to make a friend feel better and misjudging how to do that in the middle of the night. You should definitely bring it up with him, though. That's a line crossed - even if he most likely doesn't realize it.

Id be shutting it down and no he cant go partying whilst his pregnant partner is at home, even aside of these messages

Agree with the person saying if he wanted to be with her he would already x

@Notjustmeah you need to talk ru o him. Be clear about boundaries/expectations and how you feel esp given you're pregnant. I would suggest he postpones until uih can all visit her and party or go with him.

He's sailing close to the wind and I agree with others that she will be a willing participant or even orchestrator if he goes on him own whilst she is feeling crappy due to her relationship breakdown.

Sounds a bit up himself. And he isn't behaving like one of the good guys and neither is she. Friends ok but not encroaching on time through the night.
YANBU and very sorry to have this when you are pregnant as it always feels even worse . You are more vulnerable.💐

That wasn't clear but what I was getting at was that he will say it was just supportive. I think he needs to provide some assurance he will keep better boundaries in future while maintaining friendships.

Bur if she didn't read his messages how would she know what's going on?

All's fair in love and war.

I mean, it's within the context of bulling up a good friend who is broken hearted 'come on, you're great!! Any man would be lucky to have you!' but he's taken it too far by making it sound like he is interested, whatever his intention. And the conversation about your family crossed similar lines. It may be intended as confidence boosting 'you're worth more than any flash Harry' but hours of that late at night has made it all a bit personal and maudlin, plus disloyal to you.

It's not clear whether it's all rooted in interest or mutual ego boosting but I think one could lead to the other so I would nip it in the bud.

I would accept I was looking and ask what's the deal. If he offers to not go on the next London trip take him up on it.

I’m a “men and women can be close friends” person, and I’m in a polyamorous marriage, (all of which is to say I’m not someone who is easily made uncomfortable by close friendships and more between men and women) and this screams emotional affair to me. I’m sorry he’s treating you this way, and you deserve better.

The irony that her partner cheated on her but she’s messaging a man with a partner and a child on the way, in this manner. I can’t bear women who do this. Having been on the receiving end I find it maddening that a woman would ever be a part of that kind of betrayal. Don’t hide behind your anxiety - make it crystal clear that he’s crossed a line and it’s not acceptable. Ultimately though, you can stop it from happening so you either have to trust him (some men are trustworthy) or not. And if you don’t, he has to earn it or the relationship is done.

It's inappropriate and disrespectful. No.

Texting another woman flirty messages
Chatting until 3am with this woman
Telling this woman how gorgeous she is
Offering her a version of himself
Slagging off your family
Going off to party for a weekend when you are pregnant.

Not a great list from a partner. I would be annoyed by one of these things, let alone all of them!

It sounds from these messages that if the opportunity arose during his weekend in London then he would 100% take it. Otherwise he would be shutting down flirty comments or saying "sorry, big day tomorrow, going to sleep now" and not staying up until 3-4am.

They have known each other since being teens so presumably they could've had a go at things before, but didn't get together. Why? Has she always been in a relationship? Or was he not a great prospect when he was single and it is only now that she sees other women are interested in him that she is considering it?

Yes, I thought this. Wouldn't be happy.

I read this as though some dormant attraction has been awaked by her change in circumstances and they're very likely to have sex asap at this point. If the relationship ends with you OP they will possibly date for a few months to try and give it a go so he doesn't feel like he's thrown it all away for a shag.

... and leaving your pregnant wife behind

Not wife, partner. Makes no difference to the twattishness of this man but it might to any possible fall out.

This is how I would approach it.

”Love… can we talk about the fact that you’re on your phone messaging someone else at 3am? Do I have anything to worry about…?”

[wait for his response] and:

”You know this is a really vulnerable time for me, don’t you? I’m putting my body on the line here to grow our baby. I need to feel like you are 100% on my side, here. Do you think it’s a good time to be telling another woman that she’s like two Hollywood actresses combined? How do you think that makes me feel?”

[when he kicks off about you reading his phone… just absorb the anger and the defensiveness]

”You’re right, I shouldn’t have read the messages. I’m sorry. Like I said… do I have anything to worry about here?

Do you think it’s a good idea to be going our partying in London with […] when you clearly fancy her, and leaving your pregnant wife behind?”

He’s dipping his toe in.

I think a no phones in the bedroom rule is good for a marriage. Your spouse should be the last person you interact with at night and the first person you interact with in the morning (kids aside) before you message anyone else. Otherwise it’s not healthy.

(I say that as a phone addict who is currently getting this wrong in My marriage).

He is going to London to party with a newly single friend when his partner is pregnant? I would tell him not to come back.

Obviously, I do not have abilities to read his mind. But, seeing that we are friends for many many years and in that time we've had periods of us both being single, we had a lot of opportunities to get together if we wanted to. So, on balance of probability, I'd say there is very little chance of him cheating on his partner with me. Even if he wanted to, I wouldn't allow it.

That’s completely unreasonable of them then. Do they not like him because they think he should earn more even though they don’t and you don’t? What’s their logic? I can understand why he is unhappy about it.

I would be unhappy about those 3am texts and him going with her to a party this weekend! Can you go?

Bet he stays overnight at that party. I'd plan to be there

Haha, let him go OP. He'll try to date her and she'll drop him in a second. That will give you a giggle. She's just wanting the attention due to recent break up, they'd have dated already if she was at all truly interested.