I don't believe in saving virginity for marriage.

It's normal for human beings to have sexual desires and lust, be it guy or girl.
It's not only guys that are always horny. Girls gets horny too, more often than you probably think is 'normal'.

I believe sex is healthy and very much enjoyable, especially when it's practice the right way.

So there's a switch?
As a female, I can't just 'turn it off' unless there is something that is turning me off, which will turn me off for a while but it'll come back again soon. If I want sex, I will want it everyday until I get it. Your gf may be like that (or she may be just lying or unaware of what's happening), but one thing for sure, you cannot generalize all females as being the same as her.

Sorry, I don't believe that fact is true.
Based on my experience, some girls don't have much cramps, while some can cramp, vomit and faint when they are having PMS. Some girls don't experience any PMS symptoms at all while some need to be bedridden for few days. Everyone body is made different. Heck, I even get different level of pain every cycle. In fact, I don't remember having really bad cramps before I had sex last time.

Period cramps can be caused by various things. One should definitely get it check out with a gynae if it becomes too unbearable.

Grandparents and parents want their kids to have sex after marriage is because babies make them happy.

Anyhow, it would be nice if you could provide some solid scientific prove to back up this fact of yours.

If you don't completely believe it, then you should not have stated that it was the fact in the first place.

Don't always believe what those few people in your life say only. Most people don't know what they are talking about themselves.

He didn't say that in his first post. In fact, he mentioned that it was a FACT. The way he put it sound like it was a sure 101% cause and effect relationship.

I didn't say that you pointed it out that it is a cause and effect relationship.
I just state that the way you put it make it sound like one.

That and also because they generally use up more energy than women during sex, unless he is the one laying down while you do all the work.

Multiple orgasm actually means like you don't need to go thru the arousal stages to reach orgasm again and again.
4 stages of sex: Excitement, Plateau, Orgasm and Resolution