While I'm going to go ahead and assume your partner just wants to help, let's be honest: sometimes parenting partners make sh*t worse. Whether they undermine your actions and subconsciously pit your kid against you, or think they're helping by taking on the brunt of responsibilities, sometimes their involvement doesn't help. And when it comes to the sh*tty things your partner will do when your kid's having a meltdown, well, hold on to your butts. Nothing will test the whole "teamwork" thing like a toddler losing their mind and two parents who are, for whatever reason, not on the same page.
My partner is generally passive (until everything builds and he snaps about something ridiculous) which typically compliments my more dominant personality. In other words, and for the most part, it works. But every now and then he feels the need to step in and put his "best" foot forward, and that something usually messes up whatever it is I'm trying to do when parenting a kid in the middle of an epic meltdown. Maybe it's to be "helpful," or maybe it's because he sometimes gets a kick out of watching me get frustrated trying to reign our child in, but whatever the reason I say no to all of it.
I'm sure my partner isn't the only one to do any of the following and, sure, I may have been guilty a time or two as well. So with all that in mind, and because preparation is the name of the parenting game, here are some things your partner will inevitably do that will undoubtably disrupt the natural flow of your child's meltdown: