I think one big reason is that IF causes silent grief/sorrow/pain - the kind that other people who haven't experienced it would never understand, especially 'coz there aren't many non-IFers out there who would voluntarily be looking for info about the ups and downs of IFers (unless perhaps one of their loved ones experiences IF - heck, I didn't even start looking until I was thrust into that category!). Thus this strong current of desire to SHOUT OUT LOUD to the world (to let them know how painful and twisted and crazy it can be) builds up within.
Not many people understand either how tricky IF can be - that even after you "give up" and "stop", it can still haunt you and the wounds can still be so raw. Another problem is also that if you tell some people about this, they'll try to be helpful and in the end you'll end up feeling tired 'coz you have to explain your choices to them (and answer their questions) and depending on your mood, even their best attempts at trying to be helpful would push the wrong buttons inside you and that'll make you explode and the explosion would end up making you feel guilty and you just wished you hadn't told them about your battle but then it'd have made you felt so lonely and unsupported...yada yada yada...
On the other hand, the other possibility is that after you lashed out on them, whenever you share your IF roller-coaster ride again, they'll be afraid to say anything and you'll end up feeling like you're talking to a wall and not being supported and you want to feel upset, but you know that it's not their fault 'coz they just don't want to say the wrong things by "being helpful".
So in the end it's so hard to achieve a win-win situation when dealing with IF and the ugly repercussions it brings. Plus the world doesn't readily grieve with IFers as they grieve along with people who are gravely ill or people who've lost their loved ones.
It's hard when you're grieving and hurting so much and you feel that it's unnoticed or it's not "valid" just because you don't actually lose something "real" in other people's eyes. I think maybe one reason why I felt that urge was 'coz I wanted to convince myself that the feelings I had was valid: that I wasn't crazy or overreacting (even if the pain comes again and again and again at different times), that it was normal to feel that way. Thank GOD for the internet 'coz it's helped me feel that I'm not alone!
Anyway, I also find that people who have kids "normally/easily" don't understand the whole dynamics of what IF causes. It doesn't just affect my relationship with hubby, but also my relationship with other people, my relationship with God, and also my relationship with myself. It's hard to live with myself when I'm so full of anger, self-pity, sorrow, and pain, but on the other hand I can't deny all those feelings, either. I just have to accept whatever it is I'm feeling and deal with it.
Anyway, I haven't really felt anything extreme lately after we had that talk, but God knows what'll happen in the future. I must say, though, that I'm relearning to love myself again, to be my own best friend. I'm relearning to forgive myself and I think I'm doing a pretty good job 'coz I feel pretty light these days. :-D