I'm going to ask my boyfriend to pay half my birth control
Okay, but is he required to pay though?
Yes, this is a common issue in our relationship
It's perfectly understandable to ask a long term partner to pay for half of the birth control expenses, be it pills or condoms, particularly if they aren't covered by insurance. Explain to him that this benefits both of you and that the financial burden shouldn't be on your shoulders alone.
You aren't getting my point, he wants to propose to me but I'm making demands in exchange for it.
Your boyfriend seem to really love you but it seems like you are demanding things from him and making the marriage hostage if that can't be fulfilled. I do hope that you decide to accept his proposal because you love him, and not because you need something from him.