"
Youre the one givin up the love
Anytime he needs it
But you turn your back and then he's off
And runnin with the crowd
Youre the one to sacrifice
Anything to please him
Do you really think he thinks about you
When he's out
This is saying that this person is willing to do anything that the person they are in the relationship wants, even if he calls up at night, but they break up when they find out his cheating.
Yet they still want him so they go back to him giving up their own lives and happiness to please him, but that he doesn't care when he's out with them or alone he's just looking for another women to sleep with or have a fling with.