"... I love adventure (nothing too dangerous) but can easily put it to one side but it’s not that simple for an adrenaline junky."
So you are acknowledging that he is an adrenaline junkie. Well there is one thing common to all junkies, regardless of their particular drug, and that is that they accommodate to that drug. Their body gets used to it, it no longer has the same effect that it once had, and so - the junkie ups the dose. And ups it. And ups it. Until the dose is an overdose. Your husband won't die of adrenaline the same way someone dies of heroin. He will die chasing the adrenaline. It won't be enough, to row an ocean - he'll have to chase a world record time for it, or a world record speed for it or whatever will make the expedition hard enough to up the dose. And eventually he will put his life at risk, because it's not enough to climb KS, he'll have to climb it solo, without oxygen, using 19th century clothing and equipment.
That's fine for a single adult, but it's really, really not fine for a parent.
i have to add that he is a very caring husband and father and very present when he is home."
And how often is that? On what sort of a schedule? Home for 6 months of the year? Three? Two? One? Month on, month off? How often is he home, and for how long?
"I often hear about wives being their partners biggest supporter and I want to be that person too and not hold him back because life is short but also I have to say how I feel."
Why do you want to be 'that person'? Serious question. What attracts you to a life of putting yourself's and your children's needs second to his wishes? Were you brought up to be a people pleaser? Are you chronically shy with no self-confidence and regard him as a shield to hide yourself behind? Does being 'that person' garner you social status? I really would like to understand WHY you want to be 'that person'.
And how about husbands being their wives biggest supporter? Or is he too self-important to even consider that?
"I just want to add that he does want to there for our kids, he doesn’t want to miss out, he loves taking them on appropriate adventures but his passion is high adrenaline adventures."
Take out the emotive language, and that statement translates into -
Chasing adrenaline highs is of a higher priority to him than spending time with his children.
Think about it, OP. Think about it long and hard.