I'm starting to wonder if maybe OP has the issues.
He's emotionally manipulative to you. He plays on your emotions, your feelings and makes you think that you're the problem. Do you really feel like you're the problem? Honestly. Just think about it. If not then he is manipulating you. This is actually a prime example. Now he has you doubting yourself. I know it's hard but you need to think about your own life and let him get his together.
I know what you mean, and appreciate it, cos sometimes I do think I'm losing my mind. But what if he's Bi-polar? I want to help him. I'd love to help him overcome his insecurities, cos deep down I know he's not a bad person....Oh I don't know anymore...
Are you a doctor? Because if you're not, then YOU CAN'T FIX HIM and you cannot help him with your kindness. To think you can is egotistical. You can support him if he's willing to get medical/psychological help and is willing to go on the right medication but you certainly can't "help" him. Only he can help himself and he can only help himself if he admits he has a problem and wants it fixed.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion
You should really leave him unless you want a lifetime of this. When guys say "you could do better than me"... BELIEVE THEM. You don't deserve this. I know you say you love him, but you need to love yourself too.
The guy surely has trust issues. or you to good for him and its hard for him to accept! but then again a real boyfriend:calls you for nothing,texts you all the time,wants to see you,cries, gets jealous, is over protective and loves you. his got to understand that a long distance relationship comes with trust.if you can't trust then a relationship with him is pointless good luck.