Pregnant, Single, And Baby Dad Won’t Let Me Adopt Out The Baby

So here's the quick run down. We were engaged, got pregnant, we both mutually agreed we didn't want the baby. I am personally against abortion, so I brought up adoption. He agreed. My twin brother and his wife have been trying to have a kid for 10 years and suffer from infertility, so my fiance and I, again mutually agreed, that giving them the baby through adoption is best. They're already foster parents, and blood family for the baby, win win. Now fast forward a month later, my ex whom is an alcoholic, kicked me out of his apartment leaving me homeless in CA (brother lives in OR) and is now threatening to not sign off on the adoption. I don't know what to do. I am back at his house living here until I have enough money saved to leave my job here in CA and move back to Oregon. Currently I am playing nice with him in hopes that if we get along he will be more compliant. I don't know what to do though. Please help.