YW needs advice///

Hi all I am new here...
I am 23 and my OM is 38. We have been together a little over 2 years and both have wonderful children, mine a 3 yr. old girl and his a 12 yr. old boy and we love each other very much. The only problem I have with our relationship is that he can not get past the "What is going to happen when I am 60 and you are still in your prime?" stage. I am not your typical 23 year old, I have been married and divorced and I am ready to be settled. I love this man more than I can even begin to describe and I am scared that he will let this eat away at our relationship. He has talked about us getting married after I finished school ( I am going back to be a Rad. Tech.) and we have picked out the land we want to build our house on. I guess what I really want to know is does this ever pass or will it hang over him until it finally kills our relationship??

PLEASE HELP,
Casey