On again, off again relationships..

Looking to hear your personal stories... my ex and I have been on/off for, well, this is the start of our 8th year (I am 28 and he is 27). We tried being together, we tried breaking up. We've had a maximum of 9 months apart (even tried dating other people). No matter what we do, we can't stay away from each other. We are not committed now (may as well be) but we are working on our independent lives. I do eventually want to get back with him and build a life, but he doesn't think it's possible because we had some really really hard times.... However, he can't resist me. Has anyone had got any success stories with an on/off relationship? A lot of research and almost everything I have read says we have no hope for success, but I've read about two couples who at about 7 years ended the cycle and are now together, married 15 years later. I'm looking for more hope, because he has none.