My king is constantly getting forked by my opponent’s knight! How do I prevent this?

Look where the knight can move, and do something about it before it does.

Here's kind of a silly answer: if you keep putting your king on the opposite color square as the opponent's knight, then that knight will be unable to deliver a check with its next move.  Or if you place your king 2 squares diagonally away from the knight, then it will take the knight 3 moves before it can deliver check to the king on that square. Or: just keep your king on a different color square from your valuable piece nearby, because then even if it gets in check, that check cannot be a fork of the king plus that other piece...

Just before fork , (all three pieces) your two pieces and enemy knight must be in the same color.

To avoid fork, move one of your piece into different color to enemy knight. 😀

Knights keep forking my Queen!

Perhaps this will help you a little with your chess

To prevent repetitive knight checks,  move your king out of check diagonally, to a square of the same color

Have you tried being nice to the Knight and not attacking it?

Y'all replying to this dude 3 years too late, he quit.

trade pieces or trap pieces. and at my lower level i myself get forked a lot especially in bullet and blitz. best way i find is trade in and in rapid just take care of knights movements