To feel uncomfortable with this message exchange

[Notjustmeah]

My DP and I have been together for 2 years, we are expecting our first baby.
Generally life is good for us, he has one friend, wouldn't say they are very close as she lives in London, but they have been friends since they were teens. She's literally drop dead gorgeous, tall, skinny with abs, great figure etc.
For the whole time we've been together she's been in a relationship, so I've not really thought too hard about her, and like I said she's in London so he only sees her a few times a year when she comes up.
Now she's going through a break up and the guy cheated on her and she's is devastated. She's been messaging DP a lot more and he makes a lot of time to talk to her.
Last night he was up messaging her until gone 3am, almost 4. I had a feeling something was off, he never messages her for that long. This morning I decided to have a look while he was still sleeping, I know, I know I shouldn't have but it was really bothering me.
These messages have bothered me.

"I don't get why anyone would cheat on you, you're literally like Angelina Jolie and Kiera Knightley combined"

Then in a convo about how crap men are he was like I don't get how it's so hard to be a good guy. He then said
"If I learn how to clone you can have another me?" She replied "omg yes please that's a need"

This feels like he was saying he'd date her and her saying the same back?

The last one was from her where after he complained about my family being too money focused and not liking him she said
"They are shallow, I'd give all the money in the world for a guy like you"

AIBU to feel weird about these? He comments quite a lot about how gorgeous she is and he's going to London this weekend to party with her, so I might be being paranoid.

Some of the messages would cross the line for me (the cloning one in particular). What is their relationship like generally - jokey? Flirty?

FWIW I have a couple of close male friends so to me mixed sex friendships are normal, and a positive thing. With one guy in particular, we've been friends for over 30 years, since our mid teens. We've spent hours chatting together, have supported each other through ups and downs in our lives, have stayed at each others places (we've both lives in multiple cities). He's a very important person in my life. But we have never flirted with each other ever, never shared a bed. No one would read our texts and think we were or wanted to be a couple.

would your husband stay on the phone till 3am to console his mate? would he tell him he looks like a combo of george clooney and Brad Pitt to make him feel better? Something is off here. I think it's weird these two (being so close and heterosexual) were never involved at some point, is this because she always 'friendzoned' him? I would want to dig deeper into it and what stopped them from dating in the past. Maybe there's zero chemistry between these two and that's why they never dated and always remained friends? Many questions here, would be interesting to know their dynamics.

From my point of view he has cheated already (mentally)...always trust your gut feeling and look you was right..your pregnant with all these emotions and probably at your most sensitive about everything..I foreshore think they will hook up...she will probably just use him to make herself feel better and he will be either gutted she used him because it sounds like he really is into her..or he will realise he's made the biggest mistake of his life...you are a couple and should be able to look at each others phones...confront him and lay it out on the line..I would give him sn automaton that if he goes then he cannot come back...you and your baby should be the only thing he wants and cares about..your worth more than what he is giving you...how would he like you doing that to him???..
I really hope you work thingy out for you and baby..sorry if I sound blunt but sometimes it's better to say it how it is...
Be strong xxx

Lots of people here saying you should :nip this in the bud'. I'm going to be totally honest with you. You have no control over what is going to happen here. The only thing you have control of is how you respond to this. A favourite mantra of mine is 'Let people do what they want to do and you will see what they'd rather do'. I would tell him you know and that's it. No ultimatum, no treats to leave. Just tell him you saw the messages and leave that with him. Then see if he decides to go and/or continue to be in contact with her. His response and actions will tell you all you need to know about what he values most.

I agree you can't control someone's impulses however when it comes to being interested in another, people go underground rather than allow themselves to be observed. What I for one meant by 'nip it in the bud' was bring it into the open as far as you can. Let him know his behaviour has been seen. It's breached the bounds of what OP finds acceptable in a relationship and she would prefer he makes a decision if he wants to carry on flirting. That way there is no confusion that this behaviour is seen as just friendly.

100% this! I don’t want to know that the only reason my partner hasn’t pursued someone is because he’s aware I’m onto him, I want to know what he would do if he thought he could get away with it and act on that.

OP, I don't know what you should do in this situation really, although personally I would just talk to him and explain how you feel (calmly and gently). He might just be trying to be a good friend, but I think he needs to understand that you need his support. As much as he should be a good friend, you and your baby should be his first consideration, I personally think you need to have a gentle but frank conversation.

However, what I came on to say is, unless you are going to explain to him that you read his text messages (which may be what you choose to do anyway), you might want to ask Mumsnet to take down this post. I came to it as it flashed up on my Facebook newsfeed as a suggested read, so it is quite public. The text messages would be very recognisable if you partner or his friend read them, so you might want to consider asking Mumsnet if they could remove the post

What your partner is currently doing now with you is also a form of cheating, it doesn’t have to be physical and usually conversations like this would be a gateway to a bigger thing awaiting. Going with her for a party now definitely does not sound healthy. If you would say the same “cloning” thing to someone else who can potentially be a threat to your relationship, would your DP encourage it?

If your very close friend had a partner during that time in your life, it means you both need stronger boundaries with the parameters of your friendship so no hurt feeling or misunderstandings happen with both of your partner's.