"The fact I can ask for and receive forgiveness thru the Sacrament of Confession for ANYTHING--except the horrible sin of a failed marriage seems to me to be disordered logic also."
It is disordered logic, yes. Fortunately, that's not what the Church teaches.
(1) a failed marriage is not in itself a sin; and (2) there is nothing that cannot be forgiven (except that speaking against the Holy Spirit thing, and I don't understand that).
To be absolved, however, you must resolve not to continue in the sin in question (Ideo firmiter propono, adiuvante gratia Tua, de cetero me non peccaturum
peccandique occasiones proximas fugiturum.).
A priest can hardly absolve a person of a sin if the person expresses the intent to continue in that sin.
It may be a hard teaching, but it's not something the mean old Church just made up to keep people from having fun. Our Lord Jesus Christ himself said (Lk:16:18: 18) "Every one that putteth away his wife and marrieth another committeth adultery: and he that marrieth her that is put away from her husband committeth adultery."
A marriage can be annulled -- that is, judged never to have happened -- for several reasons. In such a case, the people in question were never married in God's eyes and so are free now to marry.
However, if a person's marriage doesn't meet the criteria for annulment, then that person is not free to marry. As I said, it's a hard teaching.
(except that speaking against the Holy Spirit thing, and I don't understand that).
I'm surprised you would say that. I mean, you know Latin and stuff. Isn't that stuff along the lines of John Francois and Teddy the Swimmer and others like them standing on the steps of the church, welcoming the admiration to them as Catholics (say it Cat-oh-leeks, like my Presbyterian mom-in-law jokes to get the full effect) and then voting four-square for partial birth abortion, etc. Isn't that the sort of behaviour that is meant by "speaking against the holy spirit"?