Well I'm already pushing it with spoilers since that above is the cover to Children's Crusade Number 7 which came out this Wednesday, so I'm a bastard, but here's the skinny.
After house of M, it was revealed that Wanda had gone back to central Europe to live simply. Later Hawkeye (in one of Bendis' books) found her and slept with her. It's just the sort of thing Barton does. But recently it's been revealed that that Scarlet Witch which Clint boinked was a decoy put in place by Doom so that no one would interfere with his impending nuptials. Clint boffed a fembot, and he's been made aware of this misdirected indiscretion... But the Doombot and the real Scarlet Witch, both had amnesia and didn't really understand about all the horrible things that had happened to "them" as the absolute Monarch, in her diminished state, was wooing the Gypsie sorceress with her own room in Castle Doom to "wait for him" in surrounded by all sorts of other unthought of modcons not found in the 15th century(like) hamlet Doom rescued her from.
We've known this for months if not a year because Hienberg is busy and his books ship late, but this week, after her memory had finally been restored, dropped a truth bomb by saying something like "Since the beginning, Victor has always been my side" which is when Hawkeye starts connecting the dots and asks some leading questions to Determine if Doom didn't drive her insane in the beginning of Avengers Disassembled to use her as a weapon or a human Eveready Battery to source some nefarious plot.
So, to answer your question quarter way into Avengers Crusade we discovered she digged Doom and they were getting hitched, but as of a few days ago, retroactively, Doctor Doom and the Scarlet Witch have been an item since the turn of the century back when people were first saying "but there's no such thing as chaos magic!"
This is what happens when you have a million books with a hundred different stories supposedly going on at the same time (or relative to each other).
