Originally Posted by punkrockmomma
I don't have a partner at present myself, but this is important to me nonetheless. I don't expect to be the centre of someone's universe, nor them of mine.
I'd say this is valid in any relationship - primary, secondary, mono, poly... you need to be the centre of your own universe.
I wouldn't even make an exception for your kids, because if you aren't taking care of yourself then you can't take care of anyone else to the best of your ability. When parents push themselves beyond their limits for an extended amount of time, their mental health eventually suffers, and that can have drastic consequences on the very children you're trying to protect.