[Note, this post inspired by the latest Cosmocking by Holly Pervocracy. Express written consent was given. Read it! Cosmocking is something that, when I see the link for it, I squeal! It's that good! ]
Rowdy has a theory that this "it's normal and funny to despise all exes" attitude comes from a particularly limited view of monogamy, in which it isn't enough to only love one person--you have to only love one person ever. In order to maintain retroactive monogamy, you must declare that all previous relationships were false loves, and thus despicable.
My own theory is different. My theory is that a breakup hurts, so (if you're a little perspective-deficient) you see the person who broke up with you as an attacker causing you pain. Never mind that the only way to avoid this pain is to date one person your entire life--they're still a jerkface for making you unhappy, and concepts of "painful for him too" or "painful but necessary" don't enter into it.
I actually think Holly and Rowdy are both right about exes.
If your breakup was one sided or, for whatever reason, turned especially ugly, it colors the entirety of the relationship.
If the breakup was mutual and not based in angry feelings, then you may simply be telling your new partner "Oh, I never felt this way before!" to make them feel special.
Part of it is the emotional distance of memory, as well. If I ask you about a pain you are feeling right now, you'll give me adjectives aplenty: searing, fiery, electrical, tearing, ripping, broken, etc. If I ask you about a pain you felt one year ago, I'll get "it really hurt". Memory provides distance.
It's the same for love. If I ask you about the love you feel at the moment, I could be listening to your reply for an hour. If I ask you about the love you felt a decade ago, I'm likely to get "Oh, I loved zie with all my heart" delivered in a rather neutral tone of voice. So today's love, by virtue of its immediacy, might very well feel like the specialest love ever.
But the thing is, the way monogamy is set up in our culture for women, it's risky to tell men your real "number", and it's risky to tell men you every really enjoyed sex before them or that you were ever really in love because orgasms and love are for one man and one man alone. And if you don't believe me, watch movies (Twilight), read books (fucking Twilight) and watch some TV. I love you, I have always loved you, I have loved no one other than you as if love were oil rather than wind energy.
Which is funny, because my mother, back in the 80s, used to write for Harlequin's Second Chance at Love line, which were romance novels in which both protagonists had been in love and married before, happily, at least for a period of time. The stories were about people finding love again, presented in a natural "of course you can love more than one person in a lifetime" tone.
And prior to Prop 8, I don't really remember such open frothing rage about gay people. I'm not saying everyone in the country was attending gay pride events, but it definitely seems more out in the open now.
And this abstinence only thing? I got comprehensive sex ed in high school. I was forced to put a condom on a banana more than once. Meanwhile, all of my nieces and nephews got religiously motivated speeches about crumbled up cookies and licked lollipops delivered rather pointedly at the girls in the room.
Abortion was a given when I was in high school and college. It was a right. You didn't send out abortion party invitations, but nobody questioned that it was an option. These days they're trying to defund Planned Parenthood.
I guess what I'm trying to say is, that though nobody seems to be noticing, we are, as a society, getting more conservative, in a religiously motivated way. The numbers of atheists and nonchristians might be growing in our country, but the fundamentalists are, to a large degree, winning. They're shaping the culture and shaping our minds. To such a point where admitting your have loved before, truly and deeply, is a dangerous admission to make.
And before you dismiss my concerns, consider one thing: Prior to 1979, Iran was a forward thinking, happening place. It's a little different there now.