I need your opinions

Ok so I am 19 and my boyfriend is 35. I am beyond in love with this man and I love his kids as my own. I have been feeling a little down lately because I want the whole marriage and family thing to happen to me with him. I want a baby that I give birth too and I want to get married. He’s iffy on the situation because he already has 3 kids and his ex ruined his outlook on love. He said one day he may wanna get married and have a child with me but I know him better than anyone and that most likely means not for a long time or at all. What do I do?