The man who makes everything that leads to happiness depend upon himself, and not upon other men, has adopted the very best plan for living happily. – Plato
What do you think it means to depend on yourself. Does it mean you can’t ever ask for help, or turn to someone for support? No, of course not. We 
are not islands, nor are meant to operate autonomously all the time. We can, but it’s probably not healthy.
Nor is it healthy to derive all your happiness from others. I can’t count the number of times I’ve heard kids hear at school saying, “Oh I’ll be so happy if so-and-so asks me out,” or “He’s my everything,” and let’s not forget, “She’s all I need,” and my all time favorite, “I’m nothing without him/her.” Guess what, that’s just plain wrong. Your happiness isn’t, or shouldn’t be tied to any one person, and certainly not dependent on one person.
You need to figure out how to make your happiness internally motivated. It depends on you, not on any body else. Your happiness is yours, it belongs to you, it doesn’t belong to anybody else, so why tie it to someone else? Find your happiness within, it sounds redundant to say but you’ll be happier if you do.
