I'm a new kid here. I figured out that I have ADHD about 9 months ago. I have found a doctor, am on Adderall (little if any effect yet), started a support group for adults since there was only a parents group. I'm 60+ years old. So I have lived for 60+years with untreated ADHD and the H is significant.

I have commonly taken at least part of my vacation alone, to visit my family (whom my wife does not care for) and to tour to some place I want to go without compromising and going/doing things on my vacation that I really don't want to do. My wife commonly goes to see our son and I join in later.

Is it just unreasonable to expect that I can get a week off work and go where I want when I want alone?

Occasionally it comes up and I think it might be on the horizon this year too. In the past if I can't have a 'vacation' I just stay home and work, that is less stress than a 'vacation' that is just more stress.

Do I sound like a spoiled brat?

No you don't sound like a spoiled brat

Some of my favorite vacations have been alone. There is a particular place I love to go, a residential craft school where you take week-long classes in a craft like weaving or woodworking. Particularly if your wife does not like to do the same things you like (and/or vice versa) I think separate vacations are fine as long as  you spend some time together at a different time as well.

Whether this is a problem or

Whether this is a problem or not is a question you need to ask your wife. We can all have our own opinions about vacations, but she is the one who is married to you and whose feelings you should at least consider when making your decisions. I would never, in a million years, be OK with my husband taking a separate vacation. He goes snowboarding with friends once or twice a winter, and I am totally fine with that..but we don't take separate vacations. We compromise. He hates the beach, I love the beach..sometimes we spend a week at the beach and other times we spend a week in a cabin in the woods.