This is pretty much academic since I am a spoiler ho and I intend to stay that way, but even if I weren't and I saw the scene you describe, I can't imagine thinking that Tara was seeing someone new. Especially not after TR and OAFA...the W/T attraction is so intense and they are still so completely in love with each other, there's no way either of them could be even remotely interested in another woman.
Web Warlock wrote: "So is it confirmed that everyone (except Amber) has signed contracts for next year?"
All of the original regulars--Sarah, Aly, Nick, Tony--signed seven-year contracts. Joss was kind enough to let Tony go back to England and do his thing, but technically I believe he is still under contract until the end of S7. I know that when James signed on as a regular he was also contracted until the end of S7; I'm not sure about Emma and Michelle but I would assume the same is true of them.
As a recurring character Amber is contracted for one season at a time only. As we've all been told far more frequently than I care for, her contract this season is for 16 eps.
But there's no way they won't want her back for next year. There's just no way. And I see no reason why they couldn't offer her a regular contract for S7. NO REASON I TELL YOU!