Sounds like your hitch was installed too far behind the center of the axle.
I've always had LBs and was always able to lower the tailgate. By having the hitch in the wrong place it can cause problems when towing (sway, not follow properly, jack knife..etc.)
The hitch should be centered over the rear axle if possible.
Just a caution- make sure your wife stands off to the side while hitching or unhitching. There have been cases where folks have been crushed if the pin slips off of the hitch plate and the trailer wasn't properly chocked to prevent movement.
