You're are not losing it. You are normal. A lot of women in your situation on these boards wind up on anti-depressants for a few months. If you get to the point where you are not sleeping or miserable, just get assessed for it. You can choose at that time to take them or not.
Unfortunately there may never be an answer to the "why." That's the hardest part. If he did this before in the past when depressed, that's probably the why.
Don't know what to say about your MIL and whether or not she holds out hope. I'm sure she'd rather see her son not dumping his children.
You're grieving right now and that's why you feel like you have to wear a mask. Hope some positive comes your way this week.
