I'm in the US on an F1 visa right now. I plan on getting the OPT status change after graduation and would like to start a business with my boyfriend (who is US citizen). The business will be in my field of studies (MBA, so any business should be in my field of study right?)

Here are my questions:
1. What form of business should we start? (my professor said LLP would be the only option)
2. Can I earn money while being self-employed? I will be doing most the work (production, marketing, accounting).
3. When we get married and I get a green card, how can we ensure that the business continues to exist?