Your husband may not be willing to change his behaviors for a few reasons. One, he may not know how. When someone is used to handling a problem the same way, they may not know how to change what they are thinking and feeling so they can do it differently, even if they are aware that how they are handling it isn't working. That is why therapy is so helpful (if the therapist is supportive of changing the behaviors). It helps the person recognize how their current behavior is not working and helps them find better ways to think about the problem. By changing their thinking they can approach the problem differently.
Your husband could also not want to change. He may see your issues as something he simply does not want to deal with. Some people are more inclined to think of themselves first and may not see a need to put others first. It can be a personality issue, such as narcissism, or just a personal choice. Some people do not feel they need to be burdened with someone else's problems.
Lastly, your husband could have an issue with your illness. Sometimes people are fearful of being too close to someone who is ill. They may fear being ill themselves, they are afraid of vulnerability or they don't cope well with someone who needs help.
You can two different steps in viewing your husband's behavior. One, seeing him as being self centered and emotionally detaching from him. That means becoming more independent of him. Stop asking him to spend time with you (you will not need to cope with the rejection anymore), stop doing for him and stop interacting unless it is necessary. Giving less to him will help you focus more on your own needs. This is not ideal if you want to heal your relationship, but for the time being it helps you protect yourself emotionally.
Two, you can try to view your husband's behavior as his fault, not yours. There is something going on with him causing him to react this way. It may be his fault, but it may not be. He may just feel lost and not know how to handle it. Back off from asking him to be with you and give it all a break. Occupy yourself as much as you can. If you cannot go out, have others in. Throw a party or just have some social time. Spend more time with your kids. Start a new hobby. Chat on line in a support group or as part of a hobby group. By occupying yourself, you take away the time spend trying to cope with your husband's behavior.
Also, you may want to write things down in preparation for your therapy. This is a good time to sort out your thoughts and write down your concerns. It will help you when you get there to address how you feel without having to remember it all.