Advice please, ladies.

My husband and I have been ttc for the past 2, almost 3 years. I’ve finally gone to a doctor to try and get things going so we can have a baby. She’s started me on Metformin and birth control to regulate me and boost our chances. She told me she wants me to do 3 packs of the pill and then immediately start trying again. I am on my final pack now and my husband has now told me he doesn’t want a baby right now. I don’t understand why he would just up and change his mind after almost 3 years. He says he wants me to stay on the pill for a few years. I don’t want to wait a few years for a baby. We had agreed to have one now. Years just isn’t an option for me. I want a child now. Please give me some advice. How do I go about talking him into a baby again? Maybe he’s just worried because we’ve suffered a loss already and he doesn’t want that again? Please help me.