I think the difference between the relationships you describe, and the relationships that are healthy is that you are willing to pay the price.

I agree with stopdog, there is a price for every single relationship we have. Love is not about never getting hurt, or having some always meeting your emotional needs. In fact, just the opposite perhaps. Love is accepting inevitable hurt, and being willing to do it anyway. Love is about moments of receiving, not perpetual taking.

Think of the relationship with your children and how you feel in it. You give up a lot to be a mother. But you are willing to do it. AND you get more than enough in return - you get those astounding moments.