You've made it man! You've got a career, a wife and kids! Be proud of that!
Take your family somewhere it will be just you and them, like a vacation cabin in the forest or by the lake. Make sure there's no TV/Radio/Internet/Cell Phone etc. Just your and your loved ones. Spend time talking to one another, especially your wife. Find out why she is drifting away. Reconnect. Those kids, even though they are teens, still need a good daddy. Get some therapy. The kids will be facing some major changes in their lives as they grow to be young adults. Your purpose in life is to guide them into adulthood. Then your next job will be that of grandparent!
I'm 47 and I still seek advice from my parents. Like you, I have a career, a wife and two teenaged kids.