I understand completely how you feel about the mails. I found a running dialog that my W wrote to OM. She says she never gave it to him, but I highly doubt it. The dialog was in journal style, with entries once every couple of days for more than a month and were glowing "I Love You You Are So Wonderful and So Perfect and We Would Be So Great Together if Only it Weren't For My Husband..." type of letters. On new years day she even wrote out a series of new years resolutions that included not spending another new years without him (ie D for my by years end) and happily raising her kids (ie my sons) together with him because he would be such a perfect father for them (and what am I--ouch).
Anyway, I only write that to let you know that this type of glowing "you are so perfect" letter seems to be pretty common. When I read it it hurt so much I couldn't talk about it - even when my W tried to apologize. After a while, the pain goes away and you realize that the letters were just deluded fantasy gone amuck and that they really don't reflect on you and you sort of get over them. You don't forget them by any means, but the pain lessons.
I am sorry you had to read them - and especially sorry that you had to get them shoved in your face by a looney OW.
Me 42, W 39, S8, S6, S2 M 11y, A & ILYBNILWY 11/08 Walking away from a bad situation.