Help, my player deliberately wants to screw with me in the sessions

If DnD is a collaborative storytelling game in which all participants involved choose to gather to have fun, then fun should be had by all. 

If a player's idea of "Fun" makes the others of the group not have fun, then encourage all folks to work together to tell an engaging, fun story. If they can't then there are other tables they can join. 

This is not meant to be a harsh statement. People are different, as are their ways of enjoyment. Encourage them to seek out like-minded folks.

The work necessary to put on an adequate game is not worth having someone break it for their fun alone. 

While that's true, D&D 5e/5.5e really isn't a game that supports PvP in any way shape or form. It's simply not balanced for it. If a person needs/wants to do PvP to have fun, then D&D is not the game for them. There are other TTRPGs that better support this, such as Paranoia or even Call of Cthulu. The way D&D is designed, PvP is simply never going to end well - perhaps outside of incredibly rare story moments that more or less avoid anything mechanical with a group that has implicit trust in one another.

I agree with a few other people here. This doesn't sound like an issue to solve in-game, because you're not having fun and it sounds like he might deliberately trying to ruin the game. Personally, I think "let him suffer the consequences" is for when it's all in good fun. But when you say they're "trying to get me to become more stressed and mess up as a DM, they have kinda been using the same sort of reasoning of 'it’s what my character would do,'" that's not fun and that's not playing the game with you. 

So I'd just talk to them. Not confrontationally. Just say that you don't enjoy this, and ask them to stop. Tell them what you told us, it's not fun when they deliberately break your game and it's making this stressful. If they agree then, great! Chalk it all up to a misunderstanding and roll on (literally). if they refuse, then stop playing with them. But personally, I really don't think table issues can be solved with game mechanics.