When I read the title of this thread I thought it was something different. It's been so long since I've had unprotected sex that I forgot that people used to worry about getting someone pregnant.
Back when I was with my ex-girlfriend her monthly cycle was cause for panic. I was amazed at how much a period can change some women. Growing up I never knew if my mom was on her period, and I didn't know any girls who's demeanor changed enough for me to notice, but that changed when I met my ex. Everything I knew about pms had come from listening to Roseanne Barr's stand-up, but she didn't even begin to describe the degree of change I saw in my ex. Everything I said, be it compliment, question, salutation, or death threat, everything was cause for a fight. On several occasions I saw her start a fight with the vacuum, often trying to wring its hose or bash it on the floor, other times simply a battle of words. Now I'm a sensitive guy, and I've read the mars/venus book, so I knew what I was supposed to do and I tried being sensitive and understanding her emotions and I didn't try to be logical (lol, I love how many relationship help books point out that men are logical/women emotional, sounds so condescending but can be true at times) but I couldn't do it. I tried to be nice and caring and not reply to her mean words with mean ones of my own, but it was impossible. She kicked me out of the house every single month I lived with her. I was homeless at least one night a month, every month for 2 years. I am sure my ex was an extreme case because she acted the same way to everyone once ruining her parents 65th wedding anniversary on a Caribbean Cruise by standing in the hallway screaming that she would f'in kill her sister. Anyway, the question I'm trying to get to is how much control does a woman have over her emotions, do any of you go through these extreme shifts in personality?