Welcome to the forum!!
FYI - Assuming you are using copper direct burial cable, you can go 70' from the breaker to the outlet box, and then have your 25' 10/3 cord before you need to go to #8 wire.
The difference in the 10/2 cable and the 10/3 cord markings is the ground wire, it is insulated and counted in the cord, but it is not insulated and not counted in cable. Your hubby is right 10/3 cable would be for 220v.
All the other possibilities Hutch listed are good ones, but if it is immediately pulling the voltage down and kicking the breaker, it is most likely a locked up compressor. Another possiblity is that there usually is a capacitor that gives a "kick" to the starting surge of the motor, and if that's bad the compressor motor might not start.
2004 Dodge Ram 2500 Club Cab 4x4 CTD
2007 Sunline Solaris T-276-SR: Misty Blue/Cherry
2001 Dodge Ram 1500 Reg Cab 4x4 OFF-ROAD