Did my time with an open relationship, too much work to keep multiple woman happy and for them not to get jealous even if they have something on the side too. If you have a ton of hobbies, I don't know how anyone can sustain an open relationship.
The sad thing is that o'malleys chick doesn't even seem that into to him romantically and you bet your ass she's getting more play than him while he's out there doing his two a days training sessions for months. When he does get some side action, she already has gotten ten dudes.