Anyone who lives with a woman knows that some times of the month are more trying than others ... we are all adults and we can use words like menstruation and so forth without cringing right? Right!
Anyway: I've wrestled with this for a while and came up with something that actually works quite a lot of the time.
The first problem is to deal with the name. There is too much baggage with practically anything proper so I cast around for something improper that had the kind of spin I wanted and hit on "moontime". I need to know when her moontime is coming so I can be extra sensitive around that time and I may be distracted ... tell her that and she'll keep you posted.
The next bit is that she will be thinking "oh no, my moontime again" or something similar. I've noticed women beat themselves up at the drop of a hat and beating someone else up is really just light relief. The secret is, when the moontime goes from tension to the actual bleed, celebrate.
You may think that's an odd thing to celebrate but trust me it is a great idea.
Have a special evening for her, and don't let her do housework or cooking or anything unless it is something that especially lights her up. No chores. Special dinner - wine - the works. Chick movie - foot massage - essential oils - you know the drill. It's worth making an effort and importantly: don't expect her to put out. Banish that idea - you are being sensitive, selfless, and caring. It's an investment.
And you know what? No more PMS in most cases.
When she feels the tension build she will be all "Oh goody, celebration time." And she'll happily tell you about it good and early so you'll be ready. Sometimes she'll want to do something for you too and that is good because it means it's working ... but make sure she understands that you are OK without and this is her special time no pressures or expectations and you have to mean it.
Even when the PMS is usually pretty bad, this approach makes it shorter in duration. The bonus is that the other end of the month lasts longer, and that is where all this investment pays off big time.
Note: this works if you are a man or a woman with a woman partner - though with two women their moontimes often synchronize and they need to do something special together ... I mean really: I can't solve everything.
That's it in a nutshell, customize to the individual and enjoy.