When jealousy rears up, it indicates that something inside of you is afraid. It's an alarm, nothing less and nothing more. Treat it as such.
When you begin with the premise "I treat everyone equally," you have already blinkered yourself from seeing where you don't, or can't, or shouldn't. There is no way to treat two people equally, because they are each unique, with respective strengths and weaknesses.
Relationships tend to be flawed because they are made up of inherently flawed components, mere human beings.
In a sane world, a term like "chronic crisis" would be instantly seen by anone as an oxymoron. Nevertheless, that's the state that many of us Western Worlders live in, provoking crisis after crisis so that we can justify our dis-ease rather than addressing that directly.