Ok, first, I don't believe you are Bob Dylan. Secondly, I have no complaint about using very old songs as a basis for a rewrite, what I on't like is someone taking a modern song, rewriting it and calling it his/hers. If the original auther is dead, fine, but, it's just good manners to wait until he IS dead!
Now, on the other side of the coin; Don't think twice is a better song, and, Bob Dylan is a master talent as a songwriter.
As far as his treatment of Joan Baez, I don't know anything about it, so, can't comment. He may have a personal problem, not uncommon among geniuses.
Finally, I've always been in love with Joan Baez, never with Bob Dylan. So, I'm biased, get over it.