yah, there's no doubt about that...
A good training partner who will show up everytime is invaluable, because it provides motivation for you to show up knowing you have a committment to keep and when working out, they will force you to push yourself harder than what you would probably do otherwise if you were alone.
I used to train every morning Mon-Fri with my training partner doing cardio or weights, then wrestle at night, as well as usually wrestle at least once on a Saturday or Sunday if not both days.. It was some pretty intense training and there's no way I'd be able to keep up that sort of training in the morning on top of wrestling at night without a training partner. I was in fucking good shape though, 8kgs lighter than what I am now.