Shouldn't worry jez,

We all change all throughout our lives. I'd worry more about not changing... cuz you're either dead or live like a zombie. LOL

Do you eat exactly the same foods as you did when you were young? Have some of your tastes "matured"? Like spicy foods that you didn't as a child? Or even some "exotic" foods that were just icky back then? Calamari? Sushi? Maybe even eggplant. LOL

So why wouldn't your sexual tastes mature and change over time. Nor should you presume that this is a permanent phase either. Something you may always enjoy, but you can get your fill of this too.

In reality, I believe it has a lot to do with how we feel about our partners. We ALL do a lot to please our partners... and for a submissive, this is a particularly large truth.

I'd not worry... just enjoy.