As my username suggests I'm a bloke with two kids. Let me respond to each of your points in turn:
"They don’t have as much society pressure to be nice and not be themselves"
How would you know? Society puts pressure on everyone. Unless you've been reincarnated and can remember your previous life as a man, this statement is nonsense.
"They don’t have so much biological changes just to become a parent"
This is true but that's just biology. If you don't want to give birth you don't have to, you could always adopt. It's your choice. There's nothing that can be done about this - it's just life.
"They don’t have to go through labour or pregnancy or the full time job of breastfeeding.. so their bodies don’t take a physical toll and don’t age"
I wish it were true that I don't age..... My eyesight is now knackered and my joints ache every time I wake up. Note that Female life expectancy is FOUR YEARS LONGER than for men.
"Their Careers and lives don’t take s hit when they deliver a baby"
I wanted to take more time off but I was only allowed 2 weeks paid leave while my wife was entitled to 6 months on full pay and 3 months half-pay. Personally I couldn't give a toss about my career, I work to live not live to work. My family means more to me than my job, it would have been nice to get the opportunity to spend more time my kids when they were young but that wasn't an option for me. You're in a lucky position you should appreciate it.
"They don’t suffer mum guilt if they decide to pursue their lives.. because to them that’s normal."
I don't agree there's any such thing as normal, we're all different. You have no idea what guilt I feel than I have of what guilt you feel.
"To them age is grace and there is no biological clock... very carefree"
Yes, men are immortal. Very perceptive. You should be a doctor.
"I resent DH sleeping through the night while I have to get up breastfeed.."
And does he resent going to work when you get to spend quality time with your children? If this is a problem to you, why not suggest that you go work and he looks after the kids. Don't blame 50% of the population for your own life choices.
"I love being a mum, always wanted to be, and want more kids, but It comes at such a huge cost that doesn’t seem to affect him as much."
Your choice in life, if you don't like it change it.
"I find myself snapping a lot because I feel annoyed at the changes I had to my social life and my career and my sleep and my overall life. Even though it was my choice.. because I feel it’s what best for my child. But I can’t help feel resentment :S"
And if you're DH - who you don't seem to like very much - "snapped at you a lot" - would that be verbal abuse? I feel sorry for the guy.
Seriously, I get where you're coming from and if this was a jokey sort of post it wouldn't rile me but compared to some of the people who post on Mumsnet with REAL problems you have nothing to complain about.
What you're actually complaining about are the decisions that YOU have made yourself.