I don't always agree with Dr. Laura, but I think she was absolutely right about this. People with low self esteem often tend to gravitate to people with whom they feel equal, or even superior.
This is why I often see hard working men or women coupling with partners who don't work, have substance problems or have other problems which bring both of them down. A man or woman can be a really good person, but if they believe they are not, they will pick partners who are not equal to them and who bring them down.
Insecure men connect with insecure women and their mutual insecurity dominates the relationship. Jealousy, controlling behavior, paranoia, passivity, dependency, clinginess and neediness come together to create agitation based on fear. Both fear they will not be able to "keep" the other and this insecurity results in behavior that usually perpetuates this belief. Their mutual fears that they are not good enough result in a self fulfilling prophesy of relationship failure.
The solution? Obviously they each need to work on increasing their own self esteem. If this relationship fails, they also need to choose more carefully the next time. Having the confidence to pick a partner who is functioning at a level where you want to be, rather than where you have been takes guts, but the payoff is substantial.
See also: How to Increase Your Self Esteem
Why Healthy Boundaries are Important in Relationships
I'm Looking for a Good Man...
We Teach People How to Treat Us
You Might Be in an Abusive Relationship