First off, I agree, kids can be an enormous pain. This 1 time, I was with my mom's friend (she works at a darecare. Aka she's around toddlers all the time). They weren't behaving n since my mom's friend told me that I could put them in the "corner” I took advantage of that. Then I figured I was raising my voice, way louder than anyone should do when scolding a kid. I didn't realize I was basically bullying them. kids can be such brats, but it's not ok to take advantage of your authority like that. There's a difference between scolding and bullying. As for the attitude and lying, lying so you wouldn't get in trouble. result: kid gets sent away. You do realize what's gonna happen now right? N what will keep on happening/ getting worse. He's only following in your foot steps, you know.
-you want to do as you please (have s*x and do other things "but can't because you have to babysit this brat"), and when you can't, you think life is "unfair", so you defy whatever is in ur way. Kid wants to do as he pleases, and when he can't, he acts out and defies whatever is keeping him in place.
-when he doesn't do something you want him to do, you take advantage of authority "because you can" and use it against him. When he can't do something he wants to do(or when you don't do something he wants u to do), he takes advantage of the fact that he's a rich son and gets back at you "because he can". As for "He doesn't know how to do stuff that we are good at", he's 7, of course he's not gonna be good at everything you're good at because he's at an age where he probably doesn't have to learn them yet and he's not you. If you were good at skating, does he have to be good at skating? Will it help him through life problems? Will it get him good grades? If it was something like normal chores/basic manners, sure. Otherwise, it's not justified.
"for having a huge party and locking him in the laundryroom." I wonder how this would play out if you were locked in the basement by his mom because she was having a work meeting in her house and didn't want any chance of you "embarrassing" her. "lied and told his mom he did something bad so she shipped him off to his dads for a week, but he is back. How do I get rid of him permanently?" Forggive me (seriously) but I have to ask: are you planning on killing him??? because with that description, you should really think about what you're thinking, on a wider view. Or at least go see a counselor.
"his relatives call and visit and don't like how we act?Can they call the police on us? We have both tried to tell them our point of view but they don't seem to believe us?" yes they can call the cops on u. Anyways, when trying to speak ur side, you first have to establish "ethos" (credibility). As in, the other person first has to feel like their side is understood or they'll get defensive. Remember those times when ur parents did/said something you thought was unfair. Did they ever in the slightest acknowledge your side? Another thing you have to do is admit your wrong. Remember, u need to prove ur not immature this is the way to do it.
2nd, you have to establish "pathos" (emotional connection). you know those sad commercials with the pity music in the background, begging for you to donate spare change? In this case, you need to relate to the audience ur trying 2 convince. Ex: all people have to deal with children misbehaving at some point in their life. Everyone knows how difficult it is to handle a misbehaving child.
3rd, you have to establish "logos" (logic). This is where you finally put in ur perspective. 1 catch tho: you have to keep the speech on YOU. don't drag anyone else into this. Meaning don’t say, "I was trying to stay calm, but he just kept taunting me". Don't try to justify urself. Say somting like this: "I was trying to keep calm, so I distracted myself. It was hard, though (never use "because of this" or "but..." it tends to sound childish). I was trying to prove that I was strong, but finally it became too much" If u bring the other person in, it tends to look childish cuz ur not taking ownership .Instead of saying "but he made me" I basically said "I gave up". c the difference.
u mentioned u feel bad because his mom doesn't spend enough time with him. You know what u could do? You could talk to his mom about this. Remember what I said about ethos, pathos, and logos, and use it to make his mom see this.
have a little patience with him. treating him like garbage isn't helping him relive any tension. If he tries to blackmail u into, let's say, getting him ice cream, but u know it's not a good idea, try introducing him to alternatives. What if ur family or maybe ur best friend barely spent any time with you because they were so busy with work or school. What would u do to get their attention, even in the slighest?