Manipulation, i would assume, if your friend gets every man she wants.
I dunno if this is relevant to what youre asking but i think a lot of people make compromises to get the life they pictire for themselves.
Example, i know a woman who just wanted to have a baby and be a SAHM and she was early 30s. So in the end, she just got with this guy who is nice enough, and very kind, but not the most exciting person to be around or very good looking. He has a really steady job too and had never had a girlfriend.
Now she is indeed married to him and a SAHM.
The impression i got from talking to him was he wanted a family. When you see them together you can clearly see there is no chemistry there, they dont really laugh together or share views, or even look at each other much.
So basically, they came together out of a singlemindedness. She wanted a baby and not to work. He wanted to be a family man (i guess).
People who get what they want usually do so by applying the same bloody mindedness they would if they were at work. They dont let themselves get swept up in emotion, or their instinct, or what feels right, they approach it pretty clinically: I want X, what do i have that X would want, what are my chances, what plan do i need to execute to make it happen?
These people tend to be more set on protecting their status or the status quo, because again, they will be weighing up benefits, disadvantages, costs, outlay and risk - all in an emotional sense, of course. So in the couple i gave as an example, i would bet quite a lot of money on the fact that if one of them cheated, the other would forgive: they feel they have more to lose by leaving than they do by staying.
In short: the key i think for these people is approaching a person or relationship exactly as you would a work project.