I'm not married, but there isn't much difference. Every time we move, my girlfriend's parents bring down their trailer and help us. It's always 2 full days of them telling us what to do with our things, how much they don't like the new place and what a cheap *** I am because I'm not springing for the more expensive toilet paper. We always move at the end of November, and they always drag their feet the day after we move and hold off another night because of possible snow.
This means that when I'm at the point where I really need a god damned beer, my girlfriend won't go out because her folks are here, and gives me the stink eye when I head to the bar. Stink eye be damned, several days of having my every move criticized by an overweight, aging and menopausal version of my girlfriend drives me straight to the bottle.
Quick take a look at what the Mother-In-Law looked like at your girlfriend's age. You may want to trade in the current girlfriend based on these findings.