We're also a married couple with a pretty new DD/lg dynamic going on. We've known each other over 23 years and been together 12 years and married going on 10 years. We've had a 24/7 D/s going off and on since 2011. The DD/lg is very new to us but very enjoyable for us. We're still learning the ropes of what works for us really. We have always been more subtle with our D/s, it isn't full on full protocol all the time, but it's what works for us.
It's pretty much the same for our DD/lg dynamic, but we're still working out what works for us. It's kind of subtle too but little things. Like I don't call Him "Master" as much anymore, but now it's "Papa" or "Papa Bear" most of the time.
I'm also in my 30s, late 30s, though I've also been quite young of mind, never really feel like I left my teens. My little age is 4 and I'm still getting used to her.