The is a great thread "Lessons I've leaned in the lifestyle". It has a great post about the difference between a calculated risk and a reckless gamble being whether or not you can afford to pay up when you lose. This is followed by a post about how in every swinging couple, one is the accelerator and other the brake. The job of the accelerator is to make sure you take some calculated risks, while the job of the brake is to make sure you don't take any reckless gambles.
Having even one 3-way a month is likely altering your view of your sex life. Can you pay the price? Is it worth the likely payout?
How much additional risk vs potential reward, from more frequent? Can you pay the price?