A suggestion for you - quit assuming you can read her mind. You have absolutely no idea what's going on in her head (just as she has no idea what's going on in yours). If you guys were both mindreaders you wouldn't be in this sitch.
If YOU want to go, tell her THAT. Telling her she is "free to go" does not come across well in so many ways. It says that you're not interested in asking her how she feels, you're just telling her (and then walking off without even giving her the chance to respond = more conflict avoidance). In fact now that I think about it, it doesn't even change anything in your sitch. She's ALREADY free to go if she wants. ALL this does is remind her that she has 100% of the control in your sitch.
If YOU are done and YOU want to go, I'd suggest something like "I have decided I no longer want to remain in this marriage." or something like that.
Also.. I don't know how long til your S is out of school, but wanted to let you know (from experience) that living together once you've decided for sure to separate is VERY hard. When you're in limbo it's tough as you know, but living together with the separation "deadline" on the horizon is even worse. When my H moved out last year he had decided on a date about a month out, and ended up leaving 3 weeks earlier - neither one of us could stand it anymore. Not trying to discourage you from going ahead with this, but you may want to start thinking about where one of you could live temporarily.
Me 35, H 38; Together 13.5 yrs, M 7 Bomb 1 10/07/06 Sep'd 1/14/07 - 4/15 Piecing: 4/07 - 9/07 Bomb 3 10/11/07: Never loved you, let's separate 2/08 slowly improving 7/08 Piecing (7/25/08 rings back on!!) Current thread