Count yourself as fortunate if you ever fing a "good" partner who shares the same goals and dedication as you. It's been the hardest thing for me.
The only partner I ever had that fit the mold ended up taking a job on third shift, so we parted ways on schedule, then I moved. He pushed me and I made great gains. Truth be told, at the time I was probably holding him back.
Since then I have had many partners who were good friends, but lacked dedication. I carried most of them and they would see great gains, but laziness would catch up with them and they would quit going to the gym.
A 'GOOD' partner can make ALL the difference as far as gains and motivation. They are just hard to come by.