AIBU asking him to stop talking to her?

[HoneyDewBee]

DH slept with a woman approximately ten years ago. He's still friends with her and has a lot of mutual friends in common. They all partied back in the day together so unfortunately for me, there's a handful of his female friends he has slept with that he remains friends with until this day as well as the odd texts, happy birthday/ Christmas from his exes which I'm actually fine with.
However, the first mentioned woman (that he had a fling with ten years ago) continually tries to interact with him on social media.
She responds to his posts telling him how attractive he is and asks where he is, how he's doing etc. she knows hes with me. She is very flirty towards him, and even though he is cordial, he responds to every message she sends.
There's a lot of people who message DH but he doesn't even bother opening them so I am perplexed at why he doesn't respond to half his male friends, but always does to her.
Part of me thinks he likes the attention. He doesn't have to respond, but he does. It's usually a thank you and life update etc, but this just irks me.
I'm having a hard time with him telling me that I have nothing to worry about, that she is a friend of over 15 years and I'm overreacting.

Every time I talk to him about how I feel, I get a backlash and he becomes very defensive. It gets me down. Would you be upset, and what course of action would you take?

I'd tell him I can't be in a relationship where there is a woman lurking in the shadows and if his relationship with her is non negotiable for him then it's a deal breaker for me and I'm out.

You can't tell someone what they can and can't do but you can decide what you will and won't accept.

Just don't say things unless you are 100% going to follow through. It's not about blackmail or ultimatums or empty threats. It's about what you do and do not want to put up with in a relationship.

You are not being unreasonable at all OP.

If this woman is flirting with him and complimenting him he should be cutting off contact with her. By replying to her he is actively encouraging her. And the fact he reacts so strongly when you express how you feel is very concerning: being over defensive and turning things in to you would indicate he has feelings for her deeper than friendship.

You need to remind him of the boundaries of your marriage. That yours is supposedly a monogamous relationship ship but that this woman is obviously threatening this relationship by her behaviour and his encouragement of her.
The problem is you can't make him stop interacting with her and you need to decide whether you are prepared to put up with this.
I think it must be extremely difficult for youmoving in a social circle with so many women he has had sex with. I honestly would not be happy knowing so much about his past sex life any way, let alone him socialising with them still. He does sound like someone who thrives on women's validation.

She's a potential backup. That's why he responds to her messages. He likes the attention and flirtiness and gives her enough to keep her interested.

What would I do? Be busy and find your backup by which I don't mean necessarily a person, but an interest outside of who your husband is and isn't responding to. Make your life interesting. Take a class in something you're interested in. Learn a new sport. Honestly, if a man becomes more interested in another woman than me, I lose interest and detach.

If he's the kind of person that would cheat, he'll cheat. And you have your fallback, a life outside of him.

I firmly believe men and women can be friends, even if they have had sex. But her behaviour and his dismissiveness are concerning.

You cannot make him do something he does not want to do. All you can do is assert your boundaries and remove yourself from his presence.