Ha ha, I'm only 39 and have already be hit with the big M.
I love the amazing relationship that you have with your kids, and honestly I have had these fears too.
As my kids are growing up in france (we are originally from the UK) I fear that they will get french girlfriends that may have a cultural difference that could impact our relationship with us. I only had boys and so long for a close relationship with my future daughter in law.
It's a fear that will probably never happen. So I'm going to take a tip from your book and speak more openly about relationships with them.
Really beautiful article.