Very much like my sitch, DTH (just time-shifted 3 months, this happened to me back in late April). My W also decided she wanted out after she started therapy and got put onto antidepressants. Maybe the antidepressants helps energize them to take action on something that had been eating away at them (or the C helps them to crystallize thoughts/feelings that had been eating away at them but that they hadn't quite integrated or made a plan of action on).
You know, even the timing of your affair is similar to the timing of mine (our youngest kids were each around 1 year old). I think we hurt them at an especially vulnerable time (when kiddos are young and they are just a little post-pregnancy and still out of sorts). Try to be empathetic with that and when she unleashes her spew and anger on you, don't spew back or argue or reason with her. She's coming from a hurt and angry place -- don't escalate the hurt and angry. Just validate her feelings and agree with her that there's no way things could work between the two of you the way things are. If she's CRAZY spewing (beyond validation level even), just listen and, if you have to, walk away.
Me-53 W-49 D22,D18,D15 T-Since-12/2001 Married-9/2004 She Moved Out-5/28/2010 Piecing start-04/2011 Now-together Thread http://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2079304