Thank you, Tiffols! Belated congratulations on your anniversary as well.
I love the way you put this; I have to admit I was not nearly so sanguine about seeing my wife take the first steps. (But you're absolutely right, watching someone bloom into the person they were meant to be is beautiful.)
Rabbit - I'm afraid we have no kids; I wish I had more to offer there. But I also know a few couples whose kids all turned out to very flexible and "easygoing" about it.
Starshaped - I'm sure our feelings have changed, since we've been together so long I barely recognize the *person* I was when we met.

(We first met at 17, and got engaged at 19.) I'm not sure how I can explain how it's changed, but sure, over time all relationships are likely to evolve. My guess is that we're better at compromising and "fitting" each other now, after all those years of growing together. For what it's worth, transition did also feel at times like she was developing new edges and we had to figure out how to adapt to fit together again. Which is kind of metaphorical, but I'm not able to describe it much better...
And of course there are challenges to both sides - adapting a marriage is hard work, but you deserve a lot of credit for being so joyously accepting of a new boyfriend. I know quite a few trans people who are terrified of the dating market, and would be utterly thrilled to meet someone like you.