This is interesting, and fairly personal, but I will give it a go. I guess the best word I could use for our relationship at the moment is "comfortable".
There are good and bad sides to this assessment. Dad and I are pretty comfy together after marriage, moving across country, being "poor" together, having a kid, surviving cancer...and all in just five short years of marriage! We love each other and we enjoy our life together, being homebodies and hanging out with you.
I guess the flip side of this is that we don't get to do many fun and exciting new things together, and maybe there is such thing as "too comfortable", sometimes. It can get to the point where you just start to assume the other person knows that you love them and there's no reason to remind them! This is untrue, and I think can work on being more intentional in how we love each other in the day to day adventures of life.
I love your Dad for being a godly man who loves and provides for his family and loves Jesus and the church. He loves me in spite of my spitfire ways and because I'm a gorgeous redhead (ha! But true.) You can rest assured that we are committed to each other and to you for the very, very long haul!