It may not be the submissives who have tried to cause the trouble when you look at his current behavior so much as something playing out concerning jealousy issues and the like between them on a reoccurring basis.

Sounds like he is going behind her back now to treat with you to me.

All this miscommunication etc only serves to make it more evident to me why all involved parties in a any relationship poly or otherwise need to have a scheduled sit down time to engage in some open and honest up front communication.