American technology professional needs a visa. (London)

I need some help. I've been visiting the UK- I have a boyfriend here in London. I am part owner of a business in the US that does some business over here. We are technology brokers and consultants. So... I don't need a job, but I need a visa and the company is too small to provide all the info the government of the UK requires. Any insight on how I can get one without having to marry my boyfriend, or prove we are getting married as that's just not happening as of yet. I talked to an attorney and that's the rout he kept pushing.