I don’t have the breadth of experience that a lot of folks on this forum do. However I would suggest the ideal partner brings skills/personality traits that you don’t have to the partnership. A partner on one of my deals is hard-working, good with people, not afraid to get his hands dirty. We call him Eeyore because he always sees the bad in everything. On the other hand I’m terminally lazy, don’t like dealing with people but bring a lot of enthusiasm and believe everything will work out for the best.
My money partner is very detailed oriented, and is cautious. I’m only detailed enough to get happy and then full bore caution to the wind.
if you have all one-side then you never make a deal because there is always something not perfect or you make too many deals because everything is goiing to be perfect.
A few quick thoughts are “Trust, but verify”, write everything down - including your intent in any deal so your estate can understand it if you happen to pass away, figure out how you are going to get divorced before you do anything else.