there are a lot of things at work here, I think. one is your perception of your situation. I had a friend who's mom was in and out of relationships all the time. and my friend was always criticizing her mom about "why cant she just be alone? I'm alone and its fine." well this friend WAS single but she was most definetly NOT ALONE. she was OBSESSED with being with friends all the time. to the point where every friday, she was like "Oh we have to stop by here cuz I havent see group A for a while, then go to this party to see Group B, etc etc." it was SO TIRING. I just don't work that hard at maintaining contact with eveyrone. but literally this girl would never just be with herself, yet she percieved she was better than her mom for being single relationship wise.
2) I think everyone has to get used to being alone. If you are comfortable being alone, people want to be with you naturally. because you don't project this neediness outward. I think thats why a lot of people will say "when I was single, I couldnt get a date. now Im in a relationship everyone wants me." Its not only because people want what they cant have (i.e. the taken guy), but also that on a very subtle level (and sometimes not so subtle) we project a clinginess when we are looking for someone.
when I first moved into an apt. by myself, I really loved it. it was a weird adjustment at first not to automatically call someone to go shopping with me every time I went out. but I began doing stuff on my own and it was so liberating. I almost got to the point that when my other friends (some of whom STILL will not go shopping without a friend...its weird) wanted me to come, I would rather not.....cuz I'm not a big shopper to begin with and I didnt wanna stand around looking at their crap, looking for a belt or whatever they needed. I wanted to do my business and leave. haha.
I have another friend who is addicted to relationships. she goes from one to the other. wants to be serious immediately. I don't understand where the insecurity comes from. She looks like Cameron Diaz (literally) and has a great personality, but her self esteem is totally low. She just came out of a really ugly 4 year relationship, and the first guy she meets she's already talking to me like "when you met michael, how did you know when you were boyfriend/girlfriend?" SAD! and I think she will continue to find ****ty relationships until she is comfortable being alone. but she refuses to even date. she just finds one and goes with it and tries to make it serious right away...even if they have nothing in common. with her beauty, she can get them immediately...but they are often the wrong ones.
it seems to me that the best prescription for picking crappy relationships is to prescribe for yourself 6 months of alone time. get to know yourself and you will attract other centered people.
sorry so long, but this topic is such a huge one.