You are young. You have every opportunity to have a MUTUALLY honest, loving, trusting, intimate and lasting relationship WITH SOMEONE ELSE. Take it.
This guy is not your cross to bear. You are not going get kudos from anyone for sticking by him, but you are going to live in all new worlds of misery and pain if you do. Look at his parents. They have been all through this once, and again and then again and now AGAIN. They are his parents and sticking by him does THEM credit, but it makes you look like a doormat...here fella, wipe your feet on me.
If you stick with him and believe him every time he makes an empty promise, you are in for trouble you can't even imagine. I married a man like this and I had to painfully divorce a man like this. Like your guy, he didn't want a marriage, he wanted someone to replace his mommy. He wanted someone to bail him out of every scrape he got into, pay every debt he racked up and wipe his hiney for him. Thanks to him, I eventually lost my home to foreclosure, ended up $50K in debt, so sick from lupus (stress makes it worse) I can barely walk let alone work...well the list goes on, but it ain't pretty. Why would you invite this into your life? TRUE LOVE awaits you. Dump the baggage that keeps you from finding it.
One last thing, I would not worry about his parents. This is not a bipolar problem, this is a personality disorder, deeply entrenched from childhood, a true mental illness. There was a time when he could have been helped, and his parents passed this by. I say COULD have been helped, but that is not quite right. One can heal a personality disorder, but it takes a lot of work and commitment to do so. As my therapist once told me: How many therapists does it take to change a light bulb? Only one, but the light bulb has to want to change.
Your light bulb doesn't want to change.
The Lady Dragonfly
Yes, it was me...I know because I was there when I did it. Lupus sufferer, bipolar II sufferer. Currently on Indocin for chronic pericarditis related to lupus, and cherishing every deep breath without pain. Currently in graduate school for mental health counseling, class of Fall 2007. Vegan and loving it!