Something to fall back on.

Yesterday, out of some random twist, I ended up having a somewhat lengthy conversation with one of my exes.
For some random reason, what started out as a conversation about project runway turned into a discussion about life mottoes, our philosophies, and our thoughts of life in general.
He says, "you always need to have something to fall back on. A support system of some sort."
I told him I've always been rather self relient, mostly out of duty to everyone else. I work hard to make things flawless, I help other people to make their lives easier, yet who do I turn to. Not to mention, anyone can turn on you in an instant. I mean, I know it sounds like a paranoia way of thinking but I know there would be tons of people who would use my life, my inner secrets, my entire way of thinking to hurt me and bring me to my most weak and hurt position. I can't trust anyone. I mean, even Alex. He knows so many things about me, he could break me in an instant. Yet, he hasn't and out of some weird sense of feeling I know he won't. I wouldn't do that to him. What kind of people would that make us by breaking each other with our secrets? At any cost, we know too much about each other.

The point of why I bring this up (in case you're wondering)? This conversation left me thinking the whole night about my family, mainly my long lost dad (the first man who can say he dumped me).
I guess I just started wondering, who do I have to fall back on? Who can I count on and am I so wrong for wanting to be self sufficient out fear of getting hurt?