sherlock holmes, at your service, ma'dam.
There's something about "home" that makes for dull and lifeless sex. You convinced me that everything else about married life is spectacular...I believe you. But there's something about him that none of us on a forum could possibly know. That's where you have to take an active role in pursuit of the truth. Maybe his daily routine at work makes for a dull dong at home. Maybe? Is his job draining, boring, physically or mentally taxing? Sex on vacation seems to lead me in the direction that he can let it all hang out...leave the stresses of daily existence "here" and be himself with you "there". The fact that getting laid is of prime importance in your marriage...that's encouraging and pro-active on your part. More women need to focus in on sex and keep it on track, so two big thumbs up!
Diminished sexcapades while both you and he work daily jobs is normal. You're normal. He's normal. Hey, I'm flat out exhausted after a full day and if my c*ock is saying "yes", my honey on the bed naked is saying "whoo hoo", and my body is saying "no"...9 times out of 10 the body wins! That's easy to understand. There's something about every day life, his routine at the 9 to 5, whatever it is about his day that bleeds him dry of sexual energy. It's time to start investigating, Watson, and unlock the mystery that is his daily grind. And then, with a little luck, his daily grind will include you...