How Do You Sell An Established Paysite?

I own an established paysite which has been running for 3 years and is a market leader in it's niche. We have lots of our own exclusive content which we film ourselves and we have a membership that is constantly increasing, earning a very substantial profit.
However, due to a change in personal circumstances I am now thinking of selling - although the site earns substantial ongoing income, I would rather sell it and receive a lump sum and move onto other things (I have a mainstream business I want to concentrate on).
My question is that, because of the success of the site, it would not be something that would be sold cheaply and only the larger programs / studios / production companies would be able to afford it.
How would anyone on here suggest that I go about selling the site? I appreciate any help / advice you can give.