I totally get what your situation must be like, I guess I would feel pretty much the same when I imagine this to happen to me and one of my men. Totally changing the familiar and comfortable set of ground rules, even acting against established boundaries that made you feel comfortable in the given relationship and claiming to have the right to shut down and separate major parts of his life from you ... I wouldn't know with what I am suppose to work on the former 'us' to stay connected at all. You have every right to feel hurt and pain from my point of view and I hope things work out somehow. Even though I have no idea how you will manage this mess.
Hoping for the best for the two of you.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.