What have I done so wrong in life to deserve this?

I am the wife to a husband who has ADD and I am at the threshold of stepping over my husband's ADD and out of our marriage.  Since day one, we have been through things occurring over and over.  We've been married for almost 7 years, and since the beginning when things happen....it's my fault.  With just recently getting diagnosed with ADD over a year ago, I was a fool to think things would get better.  They do get better, but not for long before something happens or is said that is.....wait for it.........wait for it........yes, it's my fault!  I can say left, he'll say I said right!  We are fortunate to be the wonderful parents of 2 beautiful kids.  As the non-ADD parent/spouse I do 99% of the parenting, while working full time and attending school part time.  I am at my wits end....I could go on and on about the pornography and how inadequate it makes me feel, the women from his past who he continues to have a relationship with via email, and often telephone conversations.  And once he get's caught?  Lawd....it's all because I have not been giving him adequate amount of attention!  Hello???? If he was pulling 1/2 the weight that I am in this marriage and within our home, then he would find out very soon, that I don't even have time for myself at the end of the day let alone trying to give him a little freaking sex!

Ugggghhhh, I am so, so, tired emotionally!  There are only so many times where a person can hear that they are the reason for another(s) unhappiness!  

I just needed to vent.....