We use “may” and “might” to express possibility.
They are both used interchangeably but there is small difference between the two.

– “May” is used to talk about what is possible : He may leave me.
– “Might” is used to talk about what is hypothetical : If I do something wrong, he might leave me.

We also use them to ask for permission : May I leave the table ? Might I leave the table ?
“May” is more common for asking for permission than “might”.