My W went from being ready to leave the whole family behind, to wanting to reconcile, to not being happy and wanting a separation, to feeling guilt for ripping the family apart, to being willing to do shared custody - and I'm awaiting the next version of the story...
Your concerns about SSRI's may be well founded; maybe even accurate, but, you WILL NOT FIND A CONCERNED EAR IN YOUR WAW. I fought this battle as well with my W; she's been on Lexapro for three years. And your constant quest to identify and diagnose will ultimately lead to nothing but disappointment and frustration.
The fact of the matter is this - if you try to convince her that the SSRI is causing her to not act like herself or even irrationally, she's going to see that as an effort by you to control her - case closed. I am speaking from experience here.
If you want advice on how to stop acting like a father to your W, just re-read the posts in this thread. It's been pointed out, examples given in your own words. Evaluate your own words others have commented on, come up with 180's and execute them. That's the beauty in solution oriented therapy - once the problem is identified, the very wise people here can give you suggestions on how to alter your actions in a positive way. Only YOU have the control to put an end to the 'more of the same' behavior.