Should I tell him?

So I’m 30 weeks pregnant and the other day at my doctors appointment she said I should try pills for depression. Normally I wouldn’t resort to a pill to fix my attitude, but I read it can be harmful for the baby so I decided to try it. I haven’t told my boyfriend that the pills are for depression. I said they were like another prenatal vitamin. I don’t want him to feel like it’s his fault or feel bad/upset or anything. Is it okay for me to keep it from him? And how should I tell him if not?