OK, so I met this guy. Thought he was awesome, feels like he's the one (we're only 16)but I still think its true, I've never felf like this before.
So I admitted to him that I liked him and it turnt out he liked me to, we've been together for a while now and he recently asked about the future, if we can get married. I want to be with him for the rest of my life and visa versa.

Just one problem, his cousin.
I must admit I met my boyfriends cousin first and its thanks to him that I'm with one of the most gorgeous guys I've met. Problem is the cousin admitted that he's jealous of my boyfriend, that he likes me and that he wants to be with me for the rest of his life. He's 24. I think he's generally a nice guy but I don't want to be with him because I'm happy with who I've got. I've tried telling him this but he doesn't want to accept it, I hate upsetting people but he keeps getting depressed about it, he even cries. I've tried giving him advice to get him out of his depression but he doesn't want to hear any of it.

I've told him I'm happy to stay friends and that he's a really big part in my life and I don't want to lose him as a friend. However, he's recently been getting stressed at me and puts on a depression talk. He no longer listens to anything I say.
I don't really want to tell my boyfriend because I don't want it to cause an atmosphere between the family, I don't want to lose both of them.

They're in the usa and I'm in the uk. I was planning on going to see them this year and when I hit 18 I'm moving over there.

Sorry for the long deatails but I beg, please help!

You've been together a while now, but he's in the US? Do you mean this love of your life you've never actually seen in person? Yikes. Anyway, you can't just move to another country when you feel like it. Plan on buying a roundtrip ticket for a visit. Some countries won't even let you visit on a one way ticket without a lot of money.
We older ones all sigh whenever a teenager says 'this is the one.' The odds of that being true are astronomically small. You change by leaps and bounds when young. Think about last year's clothes and music - sorry, but people tastes are very much the same.
You are allowing the cousin to manipulate you with his demanding depression, and you aren't doing him any favors by being nice to him. You told him he's really a big part of your life?? NO, don't you realize that sounds like encouragement? You have to go cold turkey with people infatuated with you.

Anyway, since this appears to all be an online triangle, it just doesn't need a lot of attention.

I have seen him in person before, and thanks for the advice, I really appreciate it :)

Since all of this is online anyway, then you stop contact with the cousin, altogether, and just deal with your online b/f. In this way you won't be distracted by the cousin, whose behavior is unacceptable, and disrespectful, and your b/f should have put a stop to this crap ( if he knows what's really going on), and you should have stopped it a long time ago when you knew how he felt.

Do so now, and don't be involved with the cousins drama. You can stop it anytime you want, but you have to just do it.

I agree with them guys but if your bf's cousins drama don't stop move on but you should be awared that sinse your bf's cousin or who ever he is to your bf is very close make sure he don't make lies and drama up between you and your bf because belive me or not your bf will end up probably dumping you (if hes a jerk , no offence) then you will be hurt plus if your 16 n the cousin is 24! he's alot older than you .. tbh (to be honest) but just ignore the cousins drama and just live a happy life with your bf but one thing i think briefly that you should tell your bf about his cousin and if he understands then he'll probably do somthing to hes cousin because cousins & cousins understand eachother ..right... but sinse you like the cousin as a good friend dont mess things up aswell there .. i'm stuck in this situation aswell :\ me and you both... T^T

Owell good luck :) I'm 16aswell but Wishing You The Best Luck Too ♥ ☺
Byeez x

P.S. If You need More Advice <(even though were in the same situation)> I'm Here For You (=