If the company can make more money without you than with you, what do you think their choice will be?
If you can make more money without a company than with, why does that make your choice disloyal but not the company's?
There is no such thing as loyalty in most businesses.
The best job isn't always the one that pays the most, but don't think that a business will be loyal to you at their expense. That's a rarity.
It's not personal, it's business good both ways.