Melt downs are a privilege to those that serve as the stay at home partner or the partner that only works part-time but deals with the rest of the crap every day. Thus, this person is entitled to their fair share of melts of voicing their needs, wants, and being listened too.
The other partner should listen, think, and act accordingly to help the said partnes having melt downs to correct what is causing the melt downs.
I know I am currently in melt down mode. At least my partner is responding to the point, I am not as upset as I was.