A brief appearance is given of Gregory Schwarber in the same episode when Daniel and Johnny are looking through Ali's Facebook profile to find a photo featuring her husband.
It is mentioned by Daniel that both Ali and Gregory are living in Denver. In the same scene, Daniel mentions that Ali ended up becoming a pediatric surgeon while her husband, Gregory, is an oncologist. Johnny thinks Dr. Schwarber is a pretty boy, to which Daniel expressed some agreement. However this was an attempt to cover up old wounds, as it was clear Ali did quite well for herself after their break up and marrying a greatly successful man, While Johnny's life went so far downhill. Later as Ali was visiting home for the holidays it was mentioned that she and Gregory were divorced & that he had the kids for the Christmas weekend.
Although unlikely, there exists a possibility that Dr. Schwarber was the football player from UCLA whom Ali dumped Daniel for.