Hi Aelic,
First n foremost, I need to understand abit more before I can comment on anything. What do you mean by "she ahve seem what her dad done to her mum so she is doing it just in case next time I go stray"? What has it got to do with existing problem?
If she is under depression, seek treatment now.
Naturally, as a husband, you still care for her, no doubt. If you are worried for her, ask her to seek treatment and the recovery will be faster. Drag any longer, it will be more difficult to recover. For severe depression, some people will take their own life cos unable to handle anymore.