First and most important: happy Father’s Day dad. Although you weren’t there from the beginning, you were there for everything that matter. As for his dad to go I hit the cosmic lottery.
That said, although I would never begrudge anybody this special day, for me it’s always been a reminder of what could have been and what will probably never be.
I envy those people who have had a little version of themselves look into their eyes and call them daddy for the first time.