Yes, you picked the wrong time. Tonight is over. It's 2 in the morning. Let it go. For whatever reason, she wants out. You will need to explore that, but now is not the time. Repairing a marriage is not a do-it-yourself project. You need to stop trying to fix it.
Tomorrow is Saturday. You are not likely to be able to talk to a mediator or a lawyer tomorrow. So this will have to wait until Monday. If she wants to move out, let her go, but make sure that she respects your right to spend time with your son. She will have to figure out how and when you will see him before she goes. And that should be worked out in an agreement. Whatever you agree to for the separation is likely to stay the agreement in case of divorce. So don't agree to anything lightly! It is the weekend. Do not let her push you for decisions when you can't get counsel.
I am fairly certain she will want a legal S before she moves out with all the custody/money stuff worked out. She said that in the past - and I think that's what she wantns to do by going to see a mediator. Frankly I'm pretty sure that if I put up a fight in mediation for 50/50 or anything that she will go get a L right away.
I'll do my best to steer clear of concrete decisions this weekend. Boy is this weekend going to suck.
----"Et tu, Brute?"---- me:28 W:24 S4 T:6 M:4 EA Exposed: 5/21/10 Bomb: 6/20/10 (Father's Day) NC w/ OM: 7/10/10 W moved out 8/21/10 http://bit.ly/aOrZne - My sitch