what to do

My boyfriend says he won't marry me because he's afraid of a divorce. I feel that's a cop out answer. He proposed almost 2 years ago! But he took back the ring (a $10 simple band) multiple times. We have a one year old son. I'm more than invested in this! I just feel angry. I want a beautiful ring and to share a family last name! I don't want to feel the shame of being unmarried. He knew how important marriage was to me. He says he loves me. But he won't marry me! He promised to marry me before we got pregnant. Then during my pregnancy he promised before the baby was born. The baby came and he promised "soon", now he says never