ANNULMENT

We've been married for almost 4 years now. We don't have a child. Since we are fighting non-stop, I decided to leave him because it eating me up already. I mean my mental health is not good because of the fights and constant pressure of giving birth where in fact he knows I have a medical issues when it regards to this. My question is, is it possible to have an annulment with this grounds? And I wanna know how long (estimate) it will take to be annulled? (Based on my case) and How much will it cost? Thank you.