Annulment of marriage and full custody of my 2 young kids

I've been married for 4 years to my wife. She has a nursing doctorate but she acts like a "kantogirl" a lot. She has this ridiculous temper where she acts like a spoiled brat and anything, I mean anything can set her off. Imagine, she jealous of my eldest child spending time with her father, has occasionay called her "tiyanak" before (take note, she was less than 1 yr old at that time) and recently when she lost her temper at me, she actually threatened to throw a mug at our newborn baby. what mother in her right mind does that?
I've been thinking of getting our marriage annulled, but my main concern is custody for the kids. My eldest is around 1.6 Years old and my youngest is less than a month old. I want full custody for my kids and if ever only visitation rights for her. I can't imagine what she'd do to my kids if she lost her temper, if she ever gets custody of my kids. Do I have any chance of winning a child custody case in my circumstance?

I think you should have your wife evaluated by a psychologist. She may control her temper thru medications. Remember your vows "in sickness". If she isn't willing too work with you, the evaluation maybe used in your custody case