Originally Posted by
Byakko
Not really 'dated', but as mentioned, Sif was attracted to Bill at the time because he was kinda of a perfect 'Thor-substitute', sans the horse-head-alien thing. Thor at the time still has his Donald Blake persona and stayed on earth, and Loki had also play-acted as Thor kissing Lorelei on purpose to rile Sif, which both her and Thor didn't realize had happened so there was tension there that Thor didn't understand.
Couple with Bill in his debut both being worthy enough for the hammer, and legitimately beating Thor in a 1 on 1 duel while also saving him, that prolly appealed to Sif at that low point.
Bill maybe did feel some attraction to Sif, but he was also bothered by a) he was a bio-engineered beast/'man'/cyborg thing and b) he was preoccupied with saving his people first and foremost. Sif did try to make a big heroic sacrifice with Bill's ship Scuttlebutt to save the fleet, but again it was mostly her being kinda nihilistic about being rejected by Thor, rather than anything directly to do with Bill.
I think Sif did travel with Bill for a while, but I think both of them know that Sif treats Bill like a Thor substitute when Sif can't have Thor for one reason or another. I think they're both just basically good friends currently, but I haven't kept up with what they're both doing really.