I am so sorry to hear that :( ; 10 yrs is far too long. The time has come to sit him down and have a talk. Perhaps something like:
"Honey, it has been 10 years since my work space was started and it is still not finished. It is very important to me that I have my space, it is how I make my living. I really need to know when WE are going to finish it and I need a timeline that is reasonable and works for both of us.
You are my husband and partner, I love you and support you in anything you want to do; I want you to understand how much my work means to me. I am blessed to be able to make a living doing what I love; I need you to be more supportive and understanding of what I do, it would mean the world to me. When I am happy you are happy when your happy I am happy; lets work on being happy again- Your my husband and I love you.
Relationships are hard, but in the end you have to realize that you have to make your own happiness; sometimes that means taking charge of what you want and DOING it all by yourself if you have a hubby that does not think it matters.
Hugs and keep us updated, we are here for you!!!