Spouses are loyal back, businesses are not.
Not saying that you should be concerned about getting fired everyday. But if you don't create demonstrable value to your company over a longer period of time (a couple of years perhaps) don't expect to keep the job. Things are moving wayy too fast today.
Outside of my own direct experience, I can also recall many other co-workers' experiences where the companies I've worked for went above and beyond in their commitment to their employees. One time that meant making many extraordinary allowances for an employee suffering from a mental breakdown. At times it has meant extending the employment of someone who was looking for a life/career change, but the company kept on paying a salary until the employee found somewhere new to land - way beyond where the employment had any real benefit to the company. There are many others.
By all means, takes some precautions. By all means, stand up for yourself. By all means, make sure that you're being fairly compensated... but if you go into every relationship, personal or business, with your shields raised and phasers set to kill - you will reap what you sow.