1. Why doesn't my partner trust me?
Easy: women are telepathic.
There's only two things on your mind.
Counter-measure: This is a tough one, and there's really only two options - either be honest ALL the time so your behavioural profile never changes (albeit as an insensitive prick), or lie ALL the time for the same reason.
2. How come my woman always catches me when I check out other women?
Because you are as subtle as you are stupid.
Even the leader of the free world.
Back in ye olde prehistoric times there was a basic demarcation of gender roles. Men would hunt and fight, women would gather and rear kids (and conspire with other women). This gives them a natural edge when it comes to peripheral vision and subtle observation. But it's not just their superior peripheral vision that catches you out, its your own perving skills that make it so easy for them.
Back on the ancient savannah or tundra we men developed very keen, yet tunnelled, vision over range, especially when we moved on from being scavengers to hunters. Being able to spot and then visually track priority targets (prey, predators and potential mates) was an essential survival ability. And because we hunted in packs, there was little need to improve our peripheral range so long as our buddies were watching our backs. Think of your field of view as being like a sniper scope, while women have more of a wide angle lens.
Now, when you're at the pub and some chick with a balltastic rack wanders by, your scope locks onto that pair of party balloons and starts tracking. Only, because of your subconscious need to keep that target in focal view, you don't just look with your eyes - you move your whole fucking head like a goddamned turret.
Counter-measure: sunglasses only help so much, but a motorcycle helmet combined with a neck brace is better. I'd suggest ignoring 3rd party boobies all together, but that's like saying 'ignore food and water'.
3. Hey, Kidd, my woman says I've changed since we first started dating, and not for the better. What gives?
Simple, douchebag, you've just started being more honest.
And after I finished being a test pilot for Space Force I joined the Peace Corps: Ninja Division.
When a guy starts dating a girl he puts on his A game, seeking to make the best impression possible. All male mammals do it in some way as part of the whole mating ritual thing. Unfortunately, your 'best' is not sustainable in the long term. Even more unfortunately, the woman thinks that your 'first impression' efforts are actually your normal self. As far as she's concerned, you are naturally clean-shaven, well groomed and as morally perfect as you made out to be the first time you both met. As I always quote from PJ O'Rourke: "I clean my house about once a girlfriend, after that they can get to know the real me".
Counter-measure: Instead of going for the hard sell at the beginning of a relationship, try a bit of marginal underplay. If she's still willing to give you a go, she'll actually be pleasantly surprised that you're not quite as bad as you made yourself out to be at the start.
4. What the fuck is it with her monthly mood swings, tears and paranoia?
She is either an emo-werewolf or about to start bleeding. Possibly both.
Men have no conception of the hormonal rollercoaster that is the fertile female body. PMS, in many cases, is the biological equivalent of a dude scoring some badly cut meth - instead of a buzz, you get stomach cramps, sweats, mild delusions and become highly irritable. Now, combine that with their relative hyper-senses (women tend to both hear and smell better than men) and a naturally lower threshold for pain*, and you've got a wounded bear out for blood and ready to maul anyone who gets in her way.
Counter-measure: if you want your relationship to work, and to minimise any conflict therein, you will chart and track her menstrual cycle. She won't - it still dumbfounds me how so many girls forget when their next period is due, then act all surprised when PMS hits again. It's up to you to draw up a secret calendar highlighting the expected danger dates. Then, when the time draws near follow this simple rule: Stay. The. Fuck. Away.
In my case I tend to be extremely honest with the love of my life when she's at this phase of her cycle. I tell her outright that I'll be ignoring her outbursts and accusations for the next few days and won't take any of it personally due to her temporary insanity. Then again, I say this over the phone from my place which is 30km away.
* And don't give me any of that 'but women can bear the pain of chilbirth, you mysoginistic cunt!' That shit won't play because it's the 9 month exception to the pain threshold rule, during which time their bodies produce superhuman levels of endorphins and other pain control chemicals in deliberate preparation for labour.