Getting worried about working in my family's successful business.?

I am 28, and so confused... Three years ago my uncle came up to me and offered me a full time position in my family's extremely successful business which he owns ( and which I had always helped him out at on the weekends). He promised me a company car after a year, and a pay raise every year. I left the full time job I had at the time and went from being a an architectural graphic designer to managing 2 car dealerships. I currently work 80+ hours a week and are struggling to make $45,000. He told me that because of the economy the company car and raises have to be put on the back burner, but that the oppurtunity to make a lot of money is there for me being that it is my family's business. A few of my cousins work in the business and are making phenomenal money My fiancee is starting to get upset and feels that he might just be stringing me along and she wants me to consider going back to get my MBA so that I would be more viable in the job market ( which I am all for). I already have my Bachelor's degree. I've brought up my concerns to him and made a list of all that I have accomplished to further the business, to which he sat and listened to me but quickly forgot about. I don't know if my problem is that I have to be more vocal to him about what I want ( I completely understand that a person needs to put their time in at a job , but it's three years and I've seen very little growth up to this point) or do I need to start searching for a new career( which scares me , because the job market is in turmoil now. I dont want to go back into my previous field because there is really no money in it. I need some advice.