Now that we know what crushes are, when and how do they occur in a relationship?

MLU breaks it down for us by identifying several variables that may influence a crush. "Crushes can happen at any time in a relationship for a various reasons, though I think the most pervasive crushes occur when there is a perfect storm of variables," he said. 

1. Your relationship has problems. Every relationship has its ups and downs but MLU said that crushes "tend to happen when there are downs." 

2. One partner is going through strains outside of the relationship. "Maybe money is tight. Maybe work is in overdrive. Family is sick. Life really sucks sometimes, and it can make us stressed, which can transfer into our relationship. We are more tense, and show our love less. We might still feel it, it's just harder to show because we're constantly stressed about other things," he wrote.

3. You or your partner spend more time at work or school than at home. "We'll be at work or in class more hours in the day than we are at home with our partner," MLU explained. "Then he is accidentally spending more time with a coworker or classmate than he is at home. Maybe they share an office, maybe they are in all the same classes. He's not trying to seek her out, they just happen to be in the same place most of the day/week."

4. Your crush gives you what you don't get in your relationship.  "This might be kind of a cold way to think about it, but relationships can be thought of in terms of Pros & Cons," MLU explained. "For example, my wife is not into sci-fi like I am, but this classmate did. We bonded over our favorite Star Trek series, and before I knew it I had a crush. In reality, my wife has a hundred more "pros" than this crush, but this crush had a pro where my wife had a con."