You and your SO's future

Does your idea of your future change with each relationship? For example, with my first boyfriend we were engaged, if we were still together we would be married by now, and we both wanted to have two sons. After that ended, when I was in my next relationship I just wanted a small house or flat that I could share with my SO with no children and no marriage, but I knew I didn't truly love him in a way that would last a lifetime . Now I'm finally with someone that I adore more than anything, but my SO doesn't agree with marriage and doesn't want children, but has said he could change his mind. I dont know where I stand on these things anymore.. If this something that has come with getting older or does your imagine future change with different partners?