The End of a Secret Relationship

I feel like a lot of people have been in a situation, not specifically to this, but the feeling of this. I met a guy nearly four years ago and instantly we became extremely close. He is my best friend and we have had an incredible sexual relationship since the beginning. We were both fresh out of marriages. So I think the added support for each other really deepened our connection. It's basically been like a proper committed relationship just in secret.We've laughed and cried many times over the years over the fact that the day would eventually come when he especially given he wants kids would stop this secret relationship.