As I read articles on, interviews of, and blogs by the family members of people with special needs, I keep encountering apologies and guilt. This is particularly true of parents and spouses who feel guilty for wanting personal time. The sense of being trapped by a routine is a regular topic.
Stop feeling guilty and, please, stop apologizing for wanting to have a hobby or desiring intellectual stimulation — or wanting time to do nothing at all.
For parents, realize it is draining to deal with the normal needs of any child. From medical appointments to teacher-parent conferences, raising a child is one "event" after another. Even the first haircut can be traumatic. It is normal to need time away from parenting. Yes, it is more challenging to get time away if you have a special needs child, but you do need that time.
My wife has several artistic / crafting hobbies, as well as an interest in genealogy. Her hobbies are important because they are a break from work, house renovations, and dealing with me. She doesn't need an excuse to justify giving herself time to clear her head.
If you aren't emotionally healthy, how could you possibly handle caring for someone with special needs? Instead of apologizing for being human, accept it and embrace the need to recharge. You can share the results of your hobbies or interests, but you don't need to share the creative time.
My wife needs breaks from me. I'm sure there are some days when going to work feels like a vacation. There is nothing wrong with saying, honestly, you need to get away from things for a few hours.
One spouse of a disabled person told me her friends made her feel guilty for going to lunch or dinner with them. What sort of friends do that? Find new friends, is my first suggestion. People have no right to expect you to be the perfect Florence Nightingale. How utterly absurd.
Giving time and energy to caring for another person is difficult. People can't always understand the daily stress of living with a disabled individual.
Find balance in your life and don't worry about what anyone else might say. In fact, what you fear people are thinking is probably not realistic. Most people are so worried about being judged, they don't waste time judging every one else. The handful of truly judgmental jerks don't need to be cluttering up your life.
You don't need to be a self-indulgent narcissist, but you need to maintain your own identity. That identity is more than "parent" or "spouse" of a person with special needs.