I don't want to be together anymore :/

Just treat them like shit until they break up with you.

Tell them straight and maybe cry a bit that always helps ;) x

Honesty is the best. Be honest and say something like, it's not working anymore and if they ask why, tell them

...I see no point in this. Obviously you're going to have to say you want to break up, so what are you asking us for? You already know what you have to do. Are we supposed to give you a date and time of day to say it or something? Just say I don't want to be with you anymore. Simple.

You've gotta go if you've gotta go , it's never easy even if you really want out , no easy way I'm afraid.
If your sure then you have to break it to them , feel like shit , leave and then eventually start a fresh .

Just be honest. It will feel and seem like such a difficult thing to do at the time, but it's better to tell them the truth.