What is/where can I find success without the corporate ladder?

What is the balance between happiness and financial stability?
Must I sacrifice my happiness if I want x number of children (and need to financially support them)?
(Always the ideal solution but is it realistic?) Is it possible to find a job that fulfills my happiness and provides me the equivalent monetary compensation for a ‘difficult’ job?

I’ve always put happiness above everything. It’s a life motto. And I’ve found out that this is a common thing for millennials (of which, I am one).
But I’m not living my life solo anymore. I’ve got a significant other. I’ve even got a dog now! Does my life motto need to change, due to the responsibility I have towards them? I know they’d want me to be happy – but is sacrificing my happiness a worthy sacrifice to improve the lives of those around me?

I’m finding it quite difficult to obtain inner peace, as I struggle between selfishness and selflessness. Lately, I just can’t seem to find that harmony.