Form an investment partnership with my GC? Pros & Cons wanted

[Leanne Pressly]

I've invested in real estate for 20 years in Colorado. I have several successful rentals. I'm the CEO of a marketing agency I started 10 years ago and that's my main gig. 

Right now I'm building a new rental and hired a GC. Lately, he's been saying he wants to make more money and get into the investment game but he has limited capital (he has access to a HELOC for $60K at 6%). I have capital. Right now about $100K to spend.

 
What are the pros/ cons of partnering with him in a business venture vs. just doing my own thing and paying him as my contractor?

I might add I have another girlfriend who suggested we partner as well. She's a savvy realtor, owns rentals and she also has capital. Maybe I form a syndicate? Not sure if we'd buy and hold or buy and flip. I love making money but of course, I hate paying cap gains. 

So far, the pros/ cons I have are:

PROS:
Dedicated GC/ Subs to turn projects faster
Bigger pool of money to work with

CONS:
Less of control in decision-making
Going into biz with girlfriend (of 20 years) could be bad idea

Thanks in advance for any thoughts on how to structure things as well? If GC does most of the labor, would it be fair for him to put in $60K, I put in $100K but then we split profits since he's doing about $40K worth of work? How do most syndicates/ partnerships set up the structure?

Leanne