That's what an employment contract is for.
If you want me to work on weekends, put that in the contract.
I can then negotiate an appropriate wage.
If it's not in the contract, get lost.
Alternatively propose a new contract so we can re-negotiate my compensation.
If we negotiated for 160 hours of my time / month, then that's what you're getting.
And if you can't wrap your head around that, you are not qualified to run a company and probably shouldn't be trusted with any kind of business transaction at all.
I know it'll probably take you half a year to fill my position, while I'll happily be working somewhere else within the week.
Though from what I gleamed of your personality from your comments, it's likely you wouldn't have managed to get me on board in the first place.
Also did you ever consider that some of your employees/contractors may be running their own companies/business when they're not working at yours?
Do you really think they value your business above theirs?
And even if they don't, do you think they value your company above their family/friends/life?
Do you think your attitude even has a chance of inspiring different priorities? I highly doubt it.
Your company sounds like a terrible place to work.
"What is the definition of 'Toxic Employer', Alex?"
Just because you're a founder doesn't mean you're a slave owner. Those days are thankfully over in large parts of the world.