Career Confusion

I am 29 years old. I had to quit my job around 4 years back because of family problems. I run a software company along with my brother which is doing pretty good but I feel that my heart is not in software industry. Also my role in the organization is very limited to mundane jobs. This might be relevant to specify that I started another company around 3 years back but had to close it since it did not do well. I am absolutely not satisfied with my work and whenever I am free, I just keep on evaluating different ideas which might interest me. I discard all the ideas lest I should fail or it does not sound interesting or I sometimes feel that I do not want to come out of comfort zone of not working but still earning well. I do not know what interests me or what my vision is. People say that everybody has some purpose in life but I don’t know what my purpose is. I am always frustrated because of lack of fulfillment in my work but at the same time I don’t know what to do. I also have doubts on my capabilities.