I’m not supportive of ADHD husband ???


I have read and relate to so many of the forum questions and responses on this site. I have been married to my ADHD husband for 22 years. 

One "battle" that year after year, that never gets resolved (nor can we see an agreement) is with support vrs getting own way.
When my husband wants to run with one of his latest ideas and I don't express any enthusiasm, but rather  say no that is not something I'm willing to (for example  ) put all our money into, or I don't have the time to help you figure that out etc. He gets so defensive, and with a sudden mood change tells me I never support him in anything, that I just want to aruge and tell home what he can't do all the time and I'm negative etc. I'm really a very patient calm person. I don't deserve this when I'm just bringing the reality of the "idea " into the conversation. Then the second part is I would like to be able to communicate my thoughts without fear he will lash out in the anger outburst side of adhd. 
anyone have similar situations? Advice??