Thanks so much for your answer! SO much to think about.
Yes T and K have had the agreement around having more non-amorous style involvement away from home. This has been used more by K than by T in many ways, because when she's travelled she enjoys sex with people at conferences etc. Where T is more of a poly type person who opens her heart to people. The way she cheated was that she entered a relationship with someone without any negotiation at all and continued it despite K's wishes. It ended up being that T can now no longer speak to that person at all. That was a year ago and since then T has adhered to all the rules that K has asked for in their r/ship so I would feel that she has proven her commitment to her primary.
The person who mentioned depression - my GF does have depression and moving here made it worse in some ways. I don't think I was ransomed into opening the relationship. I knew the woman she was interested in starting a r/ship and like and trust her. I agree with poly and because we've done more of a swinging type thing in the past I was happier for that to be open to poly which (in my opinion) is family-friendly. My GF's lover loves our child and is very understanding of my partners parenting commitments and helps out eg: took my patient to the doctors yesterday so I could stay home with our little boy so he wouldn't be exposed to illness.
My GF had started using alcohol quite a lot since moving here which is unusual for her, but she's always been a pot smoker and that had escalated dramatically with the stress of the move and her underlying anxiety/depression issues. It had been real teenager stuff, but she really has snapped out of it, stopped using so much pot and really stopped drinking since we negotiated new rules for the r/ship. She has also started seeing a psychologist weekly to work through her depression issues. It's like once the whole thing came to a head in a bang then she really re-committed to her own health, to our relationship and to family life. She was doing her messy smoking/drinking behaviour away from our child at other peoples houses. I should mention also that she and T are good friends and she's very supportive of my friendship and poss relationship with T.
I think it's fair to say K is very threatened by the idea of T being sexual with me because she can see the connection we have and is probably frightened by it which is understandable. She has said she has a "no locals" rule so she doesn't have to see people "all over her GF" when they go out since it's a small town. T and K both have a history of cheating in r/ships and that's why they negotiated some openness in their r/ship to allow for outside contact. The problem is it allows for K's desired method of outside contact but not for T's. Luckily this is a problem my GF and I don't have, since we've both been happy in the past with the more swinging style of contact and are both happy with poly so there's no real problems around that stuff. K has basically said to T (from what I have been told by T) that if she wants poly then that's the end of their r/ship.
I take it from what K has said to me that she thinks I was bullied into opening the r/ship and that we're really fucked up as a couple. My GF and I have never cheated on each other at all or been involved on the other side of the cheating either. Our stuff has always been out there to be seen and discussed even when it's messy or awkward. I have a very open style to being involved in a r/ship that allows the other person to be who they are and me to be myself too. This has been read before as me being too accepting and "easy" on the other person by both K and T. They are both people who have a more forceful r/ship style who want to "do things" to fix problems all the time instead of ever just letting things go along to see where they head. I have learnt over two longer-term r/ships that you can't force the other person to change who they are or do anything, but you can decide your own role in that or reactions to it. I also think you can't judge an entire r/ship based on its worst times and her doing that to me was cruel. I haven't judged her r/ship based on it's worst times and I'm sure others were happy to do that when there was cheating and stuff.
I think after reading everyones stuff I'll maintain my friendship with T during her GF's absence and will remain committed to not sleeping with her. I feel already that I have tried to do the right thing and have not acted on our attraction and have "not done the crime but am still paying the time", but compounding on that by doing the actual crime isn't going to help is it? I understand the POV of the person who said to run away from their drama, but I really love T and couldn't be without her friendship where K's friendship I could give or take in comparison.
I understand Karelia's concern about my feelings for T maybe arising out of the recent dramas. T and I have gradually developed our friendship over 6 months and as we discover more and more about each other we are discovering the more there is to like. We also discovered that we share a huge number of sexual kinks too which has been eye-opening to say the least LOL! We have spent most of our time not so much as one-on-one stuff but more in a family setting and it has been really strange for me to find my feelings really growing for T when it's over stuff like doing the dishes from cooking for our kids - isn't that when you lose feelings for people normally?
But seriously it's like my friendship with T has been a Christmas gift that as the layers come off and we know each other more and more it becomes more exciting and interesting. This is opposite in many ways to my attraction to others from the past where it's been the immediate physical attraction thing + friendship but never really gone deeper.
You know what? I feel so much better just being able to talk this over with you people! My partner and I are talking about it heaps but it's different because she's involved too. She's been very wonderful and supportive though and even though this has been difficult it's also shown how much she's pulled her head out of her arse and really gotten her act together again. And no need to hold back on any answers or thought - I appreciate honesty and forthrightness.