Wouldn't work. A lightworker might be simply described as someone who seeks to give, to help others without care of the same in return, while a darkworker is briefly described as someone who seeks to receive at the exclusion of giving, which might imply they would make a perfect couple, but that's not really the whole story. No description is going to be perfect, and I'm a bit tired, but I'll try.

A lightworker seeks to give all of themselves to benefit others, in varied ways. Because everything in life is a matter of balance, a lightworker receives "payment" in knowing that they've done everything in their power to help others. A darkworker is known for taking all they can. In return, a darkworker gives chaos, out of which new things can grow. By taking everything they can, they create a vacuum that can then be filled by new things. This "vacuum" can take a number of forms, only limited by your imagination, but they can be physical or spiritual. If you've ever dealt with a darkworker and been left hurt or drained, you'll recognize how that experience helped you grow later on.

The problem with a pairing of light/darkworkers lies in the fact that they effectively nullify each other, versus balancing each other. Think of opposite points on a circle. The rest of us fall somewhere between light/darkworkers, with a tendency towards one point or the other. If you move those two points together so they become one, the circle disappears.

In effect, the transfer of energy ceases to happen, and because that's impossible, one of two things has to happen. Either they repel each other with stunning power, or they destroy each other. They can attempt it, but something has to give.

Why? Back to the "payment". A lightworker receives payment by knowing they're helping others. A darkworker receives payment knowing they're helping themselves. Giving continuing effort to a darkworker won't satisfy a lightworker, the darkworker will always be able to take more. Conversely, a darkworker cannot be satisfied by a lightworker, because they cannot receive the pleasure of knowing they've exhausted everything the lightworker had to give.

As before, there are two possiblilities, they either repel each other violently, or they're effectively taken out of the equation, because they'll spend all their effort giving and taking, and it will destroy both. Actually, there's a third, possibility, but it's probably pretty rare. The lightworker and darkworker would cease to be. Caught in a self-destructive loop (remember, a darkworker seeks destruction, but not their own destruction), it's possible they could "throw" each other out of their respective positions, so that neither is at the extreme anymore.

However, there's a problem. Both would remember the extreme pleasure they found in their old positions, and while it's a means of survival, it would satisfy neither, and either they'd secretly despise each other, or eventually they'd be drawn to return to their former selves. Essentially, moving from the extremes only slows/delays the onset of the other two results.

Like I said, I'm tired, and human speech is somewhat poor at describing spiritual matters. However, I hope it helps you visualize the matter. Honestly, this really isn't an issue, light/darkworkers have an innate understanding of this, and it's an issue that virtually never arises. It's more of an issue to those who are close, but not at the extremes of these points on the circle. After all, "love" is a two way street, and by it's nature, such love is best when both individuals are balanced with give and take efforts.

It's obvious enough, a true lightworker cannot fall in love, that would demand that they receive from another. And a true darkworker cannot love, it would mean giving to another. Perhaps nearly nothing, but that's still far too much for either.