Why are they sucking you into the middle? You are their partner not their mediator right? I've never been in a poly relationship nor would I ever choose too but I can try and come from an unbiast place...
Using you to 'one up' eachother is disrespectful and abusive...Are you happy being a part of this trio? I understand that you see it as the most understanding partnership you have been a part of but is it really if they are 'middling' you in their battles between eachother?

Maia you make an excellent point and I hadn't thought about that before. I guess it is not. He told me I stabilize them not so long ago and I didn't know what to say to that!

Like I had written before I do not know anything about being a part of a poly relationship but it occurs to me that if I were to choose this type of union that I would want to be a positive additive to a good and healthy partnership as oppose to the heavy and inappropriate responsibility of 'stablizing' two other individuals as partners...
Just a thought...we all struggle with the dynamics of relationships whether they are 'traditional' or not...best of luck. Do what makes you the happiest...if that makes them happy too, good, if not, maybe it is time to move on...?

I am going to find out tonight if what mmakes me happiest about our relationship is they same for them. I really see what you mean. What makes me happiest about it is the closeness, I love how it feels when we are all just hanging out reading or watching tv. I love the conversations we have, they are so different between us. I think I have gotten addicted to the sex I have with him. With her its different, good but different than being with a man and I have never been happy with a man (have a history) like I am with him... it is very freeing, I can't believe that women can feel this way! It all gets a bit confused in my head.

have you found any resolve yesterday evening or today...?

No I never got a chance. They kicked off in their car on our way home from a chuck e cheese. I was in my car and didn't know it had happened. Apparently she had been on one yesterday day when I was not home about how she was fed up of the baby and he decided do get us out of the house for a while. So I joined them there, my first time and all I can say is who decided to drive all parents crazy! However, the kid was enchanted and pretty much happy toddling around with a few of those coins in a cup. She decided after dinner that it was giving her a headache so she and I left him and the baby there and went grocery shopping. Ok fair enough, division of labor and all that. Apparently what happened on the way home was he said something like "are you happy I found a way to keep the baby happy for 4 hours?" and her response was "it gave me a headache". This hit his button of not feeling appreciated and away they went. I was up until 2 this morning trying to mend it and had to get up at 530 to come to school. Once again I am stuck because not only do I see both sides but personally I side with him because this issue she has about being such a princess drives me insane but even while I agree I hate to gang up on her because I feel like she feels attacked all the time. I don't know why she couldn't have said that she appreciated the time off before she complained about the noise level. She is home and completely alone with the baby for about 6 hours 3 times a week as he has an amazing schedule. I don't know how she would cope if he and I both worked normal jobs and she is pushing to get pregnant now, well if possible tomorrow would suit her. I don't get it. I might be more sympathetic to the whole I can't do house work and look after the baby thing if I hadn't trained to do childcare and didn't know how much work a high needs kid would be. He is only high needs in the fact he is super bright and needs a challenge plus he is 2 1/2 now and pretty much a year ahead of himself.
So the stress remains and this week should just add to it as we are spending time with both sets of parents. He has decided he is not going to let up on her now until she either changes or leaves because he can't deal with her sense of entitlement so my week is going to suck!