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If you want to keep your marriage intact - and it sounds as if you do - you're going to have to involve your husband in your new life. That doesn't have to mean you can't travel at least some of the world, or some with him, and some without. I don't know about the plastic surgery, although obviously that's a personal choice. It might be a follow-up to your cancer, or you could be talking about a new nose, I don't know. If your job is hopelessly boring going back to school to pursue a new career might be a great idea. Skydiving - why not? All kinds of people do it. Insure yourself (on the off chance) and give it a try. Take your husband with you. He doesn't have to jump, but he should be involved. Tattoos - why the heck not. I got my first at 35. (Just make sure you don't put it somewhere that will be three times as large in 20 years.) Quit wasting time on friendships that have stagnated, and get out of the people-pleasing mode - sounds like a good idea at any time of life.
In the end you have to do what you have to do. Part of the worry your husband and family and friends may be feeling is that they'll lose the person you are. Change is scary, and I suspect they're scared. In the end they may never understand - how can they? - and they don't really have to. As for the sarcasm and disapproval you're getting - you aren't a child, and you have to lay down some ground rules. You don't need the approval of your family, and you don't need the sarcasm. If you have friends who are treating you this way they aren't friends worth keeping. Explain to all concerned that these decisions are yours, and your husband's to make, and if they don't approve you won't discuss it with them. And then don't. All they really have to do is let you live your life, maintain a connection with you, and be supportive - even if that means shutting up.
Some of what you want to do will no doubt affect your husband and for that reason you owe it to him to share your new feelings and experiences with him. Then you have to find a balance between what you want and what he wants. Honestly, I don't see anything appalling in the things you want to do - you're not running off with some guy you met at the circus or smoking crack - so there should be some room for compromise, on both your side and your husband's. If he's worried about the impractical and unwise aspects maybe he can give you some input on doing some of this stuff in a practical and wise way. You have to give him the chance, and you have to accept that he's scared - while not letting his fear dictate what you do.
Time is running out for all of us. You've just realized it a little sooner than some of us. In the final analysis its your life to live. Go have some fun.