A great partnership is one where both sides rightfully think they got the better deal.
However, the way to get there is not by searching for the better deal but by being the better deal.
If you give more than you take, the partner will probably do the same. (If they consistently don’t, it might be time to re-calibrate the relationship.)
For people who try it the other way around, i.e. by first wanting the better deal before they are ready to contribute their part of the equation, I find it hard to believe that they’re going to be a valid solution of the equation.
You don’t look for the perfect match. You create it.