Keep bringing up Marriage

Je

My boyfriend and I have been together for about 4 years now and we are very close. In the early stages of our relationship he would say he’d marry me one day. Well I’ve brought it up a couple times and he would just be like not now...so we actually discussed it and he said he hasn’t established himself yet ? Also would bring up the fact that his parents marriage didn’t work out. This was never an issue before. Can someone help me understand what he means? My parents have been married for 27 years and both my siblings are married. I’m so ready to marry this man but I fear it will never happen....