system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why did evolution decide to require a male and female in order to reproduce, when single celled organisms successfully reproduced asexually?

Trying to understand the evolutionary benefits of requiring a male and a female when a satisfactory option (perhaps even better?) was already in place...

Wow... lots of responses quickly!  Thanks guys... I dont know if I am breaking rules, but can i throw a curve ball out there?  If multiple partners creates stronger/complex offspring... why hasn't (and can) evolution evolve to allow more than 2 involved... therefore further complicating and diversifying the offspring?
gpt
Sexual reproduction gives more variation within the species in a shorter timeframe. Variation can be a good thing.

Edit: to answer your second question, these sorts of things come about if the benefit outweighs the cost. So if it's beneficial to have a multi partnered relationship, outweighing the cost of complexity, it will eventually happen. The closest we have come that i know of are polyamory, polygamy, harems... You get the idea.