The poor hiring decision gives the University an easy out. He would have a devil of a time defending that decision in any forum and I doubt he wants to give everyone the opportunity to rehash the whole thing over and over again in multiple venues. You really have to screw up as a head coach of a revenue sport to not leave with a settlement, but Bobby did it.
If he had just paid her and not given her the job, he would still be coaching. If he had paid $50/month for his own cell phone, he wouldn't be airing his own dirty laundry through FOIA requests.
What I find surprising is the lack of outrage among the sports punditry over the relationship. Unlike politicians, apparently everyone associated with college athletics expects the HC from a BCS school to have something on the side.