People that bounce in and out of relationships are the ones that cannot be alone for fear of getting to know themselves. They let fear run their life and are dysfunctional. Im not judging, its just how I see it.

I think it is because they cannot or will not commit.

Some people can't commit or won't commit to understanding their own feelings and emotions, thus they aren't able to make a lasting commitment to another person.

Well I have know women like this.They are not always beautiful, either. There is always a similarity to them. They are often shallow and expect perfection in relationships and when it doesn't feed their needs, they bail and move on quickly. They are usually easy and welcome any male attention. They are usually players who say they want commitment but do everything in their power to sabatage themselves with their reasonable demands.Most of them are narcisists and users. It takes work to make a relationship last and they don't have the desire to do th work.

i guess i didn't get that memo either. i don't know how they do it, but i know this: a good amount of people i've known who move from relationship to relationship with no breathing space in between, it doesn't seem to work out very well. it's like people are afraid to be alone and have to have someone. for them someone is better than no one. i have a friend right now that if she'd taken a little time to smell the roses in between bf's, she probably wouldn't be in the situation she's in now. long story short, she picked up with her new bf before she dumped the old one, moved in with him and everything was great for 4 months. new bf turned on her, caused her to lose her job and has bailed out on her with no money to pay the bills. i wonder how much different things would be if she hadn't rushed into a new relationship and given herself some time to get to know this person better?

They are just lucky I guess. I mean, maybe not in the sense that they just stumble into such great relationships. But, in the sense that they are probably the type of person who is in high demand.

Everyone wants to be in a relationship with someone who is attractive, intelligent, funny, caring, compasionate, etc. And the reality is that, there are not enough of those type of people to go around.

It is like I have said before; when choosing your mate, you typically can choose up to 3 of the following 4 options:

1) Attractive
2) Intelligent
3) Great Sense of Humor
4) Single

A lot of people, especially those who feel they posess the first 3 qualities themselves, are unwilling to settle for anyone who does not also have those qualities... So, what tends to happen is those people are rarely available on the open market. Instead, they must be stolen or rescued from other relationships....

Lots of reasons I guess. A co-worker was notorious for doing just this. Her reason: '"I'm scared of being alone." Further questioning revealed she didn't like herself so didn't like her own company. Relationships provided the distraction that stopped her from looking within to see why she didn't like herself. She has my sympathy as I can see that sometime in the near future, she is going to have to confront this fear.

Maybe because they don't like dating multiple people at the same time nor do they want their partner dating multiple people.

While I agree somewhat with the previous comments, Vermilion, it's not all of a piece. People have their droughts as well as their times when they seem to have lots of people connecting with them. In my most recent relationship I fought the feelings I had for my SO extremely hard exactly *because* it was so soon after breaking up with the last person I was interested in. And she was also feeling much the same way for similar reasons. However, we were lucky to both take a chance on each other and things are moving forward nicely. As people have said, just because people are with someone doesn't necessarily mean that they are *happy*, they just have someone to be with. Speaking personally, I can't stand the idea of being with someone unless I have a solid or high degree of satisfaction or happiness with them, otherwise I know that eventually things will fizzle.

Some people just jump on the first thing that comes along...they are not happy within themselves, so they seek others to try and fill that up.

It usually does not work, and that why you see these people after a month, or even years finding new relationships...

I think it is for the same reason people can be bullies..It is because they are lacking self-esteem and to fill that void.

What you are talking about is called serial monogamy...

http://www.wisegeek.com/what-is-a-serial-monogamist.htm

However, pre why it is easy for some people to connect and not others, I think is a much different question. Maybe you have higher standards on who you spend time with, maybe you have a more reserved personality in which your expectations or 'vibes' mean that someone must demonstrate up front they are worthy of you being in their lives. Maybe others make it easier for relationships to start because they are in-love with being in-love (as my mother would say) and engage in receptive behaviors that bring people into their lives quickly.

However, I would say IMO...it is MUCH better to have few, but Quality relationships in which you have a real chance of being with someone who wants to put in the work required of a real relationship... than to have lots of superficial relationships that are doomed from the start because neither the relationship can't get past BUMPS in life that eventually happen.

I think this is because some people have issues that they are not dealing with ...

There are a lot of people who are simply in love with the IDEA of being in love.. and that's what fuels them to latch onto the next person they get along with.. Sometimes it has little to do with not wanting to be alone. Some people are just so obsessed with the idea and the potential of someone loving only them forever.. Me and my girls used to say that people like that are just "Lovedrunk"

OK, I had to revamp my answer after seeing all the others here:

Original answer:
I have a serial monogamy problem. Don't mock the afflicted. :)

I dunno how it happens, but I just allow myself to connect with people, thereby making it easier to move into a relationship, I guess.

More: I do hate being alone, and it's not that I hate myself. I just love interacting with others, and I love meeting new people. That's not to say I go from one relationship straight into another.

I am not shallow, nor do I possess an unhealthy amount of insecurity, I just really love devoting myself into a relationship and loving someone, taking care of them, learning from them, etc. There are too many people out there, sitting by myself at home all the time when I'm single drove me crazy! That doesn't mean I was desparate to find someone to be with, I am just social and when you put yourself out there, relationships are bound to happen.

Okay, I hope that doesn't sound defensive, but I just had to expuond a bit becasue many of these answers make it sound like serial monogamists are self-loathing *****, and that it not true for me!

For fear of being alone and fear of not feeling wanted romantically by someone.