Again, very sorry to hear it and for what it's worth, happy birthday (know it doesn't feel like it...).
The one thing I know is that you are not obligated to move out. She wants the D, she can move out. That is one definite thing to remember. I have already made that point very clear to my wife and our marriage counselor.
You are also not obligated to support her if/when she does move out. Your daughter, yes, her definitely not. One benefit to being married is financial support. No marriage, no support until/if ordered to do so by a judge once it's final. She is the one who wants out so let her deal with the consequences of her decision.
Not sure where they get the idea that since they want out, the husband is the one who should leave. In cases of infidelity, etc., understandable, but in cases like you and I have, no way. BUT they all try to pull it off and some people take the bait.
Have to close now but hang in there and keep your chin held high, you're on the high road here, don't sink to her level.
Me 47 W 44 D16, D13 T 23yrs M 20yrs WAW/MLC + Male EA "BFF from H.S." = Misery