I would tell him that I didn't believe that she would respect the relationship between yourself and him and that is an unacceptable trait for anyone in a relationship with you. Be clear that if he wants to pursue a relationship with her then it will be a deal breaker for you.

Of course, it does have to be a deal breaker but I wouldn't want to be involved with someone who actively wanted me out of the picture.

It sounds like you and he have different ideas about what you want the relationship to be. If you've told him what you want and why, and he's not responsive, then it's up to you to decide if you want to accept his idea or not. If you haven't told him, try that first--

How were you made aware that she wants you out of the picture? Does she feel the same way about M's wife?

Your "mutual friend" sounds like she may have had an agenda...

Maybe you should just tell him your attraction to her has waned, and that he should feel free to see her all he like, just not with you - as none of that is untrue, it seems. Maybe it's true that he doesn't really want to see her solo, and he just really enjoyed the threesome. In that case, maybe you can find someone a little less posessive to fill the bill.

I would trust your feelings or at least check them out with your partner. I found out the hard way that sometimes you cannot compete with new relationship energy and no matter how hard you try to make your partner understand that it is not working for you they simply want to keep going with the new relationship at your expense. Love is a strange beast and there is really no way to control or harness it once it has developed. Also, the more you do try to control the situation such as setting the boundaries the more you will become the problem in his mind.

I was told by a very wise person recently that polyamory only works when it works for each member of the trisd equally. It is the responsibility of your partner just as much as it is your responsibility to communicate the difficult stuff and resolve your differences in a way that works for all parties involved. If your partner doesn't understand that then your partner does not understand polyamory. It is that simple. Think of a triad as a three-legged sack race. If one of the three of you falls down it is the responsibility of the other two to lift the fallen one down and help them across the finish line. Otherwise, it is not a real triad. Also, triads are probably one of the most difficult types of relationships to have.

Sorry to be so bleak. Best of luck to you. I would love to see more happy endings when it came to this sort of thing.

Not sure what I could add to this, but I must say I agree with all the other posters. You and the others all have different ideas as to what is acceptable. If you don't speak up you will end up feeling used and not happy. Being poly means you can love a person and have another love them as well. Seems she is ok with his wife ,but not you...why? Only she knows. But his intent is to have you all fuck together and both of you are not ok with that. He can't force you guys to fall in love with each other. What is his agenda?

Ok rambling....

You're worrying about too many people.

Focus on you and your partner, and let your partner deal with their own issues, such as the cat's ear disease, whether or not they left the gas on and how annoying some chickie-babe is.

Not your problem.

I know it can SEEM like your problem. But it's not.

You have two problems, and one isn't actually "real."

The not-actually-real problem is that you got involved with someone, and now they seem to be wanting to somehow horn in on more of your life. That can SEEM like a problem, but it's not, because they're not communicating with you. So, not a real problem. A pseudo problem. Ignore that person for now.

The REAL problem is that your partner is going on about stuff that wrecks your concentration and seems potentially damaging to your relationship with them. This can be a real hassle. A very common example of this is someone who rags on and on and on about their ex. Makes you wanna knock on their forehead and say "Helllllloooo! Nobody here but you and me, baby!"

The simple solution is to make it clear to your partner that you are NOT INTERESTED in this other person and NOT INTERESTED in finding a way to include them into your life. Practice that, because if your partner is fixated on the thing, you'll be doing it a lot.

If the topic keeps coming up (and it probably will -- the condition seems to usually include cluelessness), feel free (depending on your style) to tell your partner that you will DISENGAGE from the situation if that topic comes up. Naturally, you will be tested, so expect to put your money where your mouth is.

Yeah, it can be difficult sometimes. For example, let's say you're right on the edge of having an orgasm and your partner growls how hot it would be to have both of you. That is a Boundary Test. Pass it or you're doomed. Get them to stop what they're doing, roll 'em out of the coupling, inform them that you are NOT INTERESTED in this conversation, and go do something else.

You don't have to cut them off from the rest of the interface, just be very, very precise about that one topic. TELL them you're being very, very precise about that one topic, and when the topic changes, go back to being as normal as you can. Reward them, if you like. I recommend a World Class Blowjob.

This is how you train yourself to have good boundaries and how you train others to respect them.

Usually there are two results out of this: They either drop the frickin' subject or they bail.

"Bailing" might seem bad to you, until you remember that this is a person who doesn't care about your boundaries.

I'd avoid the whole part about her possibly being in love with him and wanting you out of the picture, that sounds like unconfirmed drama, which ultimately is between her and him. I'd focus on your relationship with him and probably say something like...

"Hey, I have to get this off my chest because it's been bugging me. I've realized I'm just not into that chick and couldn't do a threesome with her, in fact it makes me a little uncomfortable when you talk about her like you do when we're spending time together. I realize you have a crush on her and want to spend time with her, and that's perfectly OK on your own time. But I want our time together to be just about you and me. I hope you understand how I feel and are cool with it, because I have the hots for you big time and you're really important to me."

Update...
I anxiously awaited the return of my honey, and was happy to finally hear that he was home. Trying to manuver around his scheduled time with his wife and our work, I had tried contacting him numerous times with no answer or return of my calls. Finally I had run into him and he was moody and unwilling to talk. I frankly stated that if he was going to be too immature to have a discussion with me...(even if it was a conversation in which he told me that he was angry at my unwillingness to participate in his fantasy) then the relationship need not continue. Im hurt...so very hurt because he was fine with it...didnt want to communicate. I guess he just didnt care for me like he had always told me.

The one really really positive thing out of all of this is that My sweet loving husband has been so supportive (even his gf has been there for me) and has been extra attentive. I am sad because this is my first try at a poly relationship, and it failed...but at least I know my marriage is rock solid...and that I will always have him.