Why Situationships Happen
They often develop when one or both people want the benefits of a relationship without the vulnerability of formally committing. Sometimes it's timing — someone isn't ready, or there's a practical obstacle. Sometimes one person is waiting for the other to make a move, and both end up waiting indefinitely.
The ambiguity is usually comfortable for one person and uncomfortable for the other. The person with less investment benefits from the flexibility; the person with more investment is left without clarity.
How to Navigate One
The only real way to resolve a situationship is to have a direct conversation about what you both actually want. The fear is usually that asking the question will end things — but a situationship that ends when you ask for clarity was never going to become what you wanted anyway.
Some people are genuinely happy in an undefined arrangement; if that's mutual, it's a valid choice. But if you find yourself frustrated by the lack of definition, the answer is in the conversation you've been avoiding, not in waiting longer.