[nicholas73]

Correct me if I'm wrong, but isn't it difficult for the employer to prove if you worked on your business while employed? Suppose you don't keep a timestamped code repository, do your market validation work that looks generic (web browsing, some calls and emails to prospective customers), don't use any company equipment, and last but not least do not blast online that you are the owner of a business.

You can then quit when it looks like the business can start generating money, and your employer would be none the wiser, right? Or heck, keep on working as how would they find out? Unless you will need to take investment, you can just keep it a secret?