Husband threatening to divorce if I take antidepressants

I'm 3 months postpartum and this period has been the worst experience of my life. The birth was traumatic and has left me diagnosed with PTSD and postpartum depression. My OB prescribed me antidepressants which I'm considering taking.

My husband is extremely against antidepressants. He believes I should work through this on my own and not seek medication (the quitters way out). He wanted me to use alternative/natural methods, but those haven't worked (herbs, working out, etc). I showed him studies that show antidepressants aren't harmful but he doesn't believe them.

I had a breakdown one day and told him I'm not able to cope with this postpartum period, and to survive this I need medication. He basically said if I use this medication, he'll divorce me and file a petition to have 100% custody of our LO. I love my husband but I desperately want to be treated. I'm thinking about just taking the medication in secret.