Coworker being kind of a jerk and I have no clue what I did.

[Seymore]

I have a coworker that I've known for about three years. Long story short, I had feelings for her for a couple years but she got engaged about a year ago, so I just kept it friendly. Over this summer she confessed her feelings for me, knowing I felt the same, and doubts about her engagement since she got to know me. Regardless, we just kept it to texting and sometimes flirting (she would flirt with me pretty heavily).

End of summer she just blew me off out of the blue. When I asked about it, she said I would never understand her and we should just keep it to hello and goodbye at work. I was pretty crushed, and it took a month or two to be able to go back to some semblance of normal (insert obligatory don't poop where you eat comment here), although I would always say good morning in general when I entered her department and goodnight when they would leave, either way.

After about a month of that, she got snippy with me out loud in front of our coworkers as I walked by, saying with a real snotty attitude: "Um...Good MORNING, Seymore.  You never greet ME in the morning". I have zero idea what she meant by that other than maybe I wasn't giving her special attention anymore, because I certainly was saying good morning, just not *specially* to her. I was kind of embarrassed and resentful about how she handled that, so I ended up deleting my Snapchat account, her phone number and any other contact I had with her.

Her birthday came around and I made it a point to be nice to her.  I brought donuts (as I do with everyone else there), sang to her along with our coworkers, and the next day I asked her how her birthday went. And we talked like coworkers. It seemed like everything was fine. When I would pass her at work, if we made eye contact, I'd just give a friendly smile as I walked by (as I do with everyone else), and she would scowl at me. I just ignored it and figured why not be the bigger person so I kept smiling and she kept scowling.

New Years Eve, before I left, I wished her a Happy New Year and she did the same. Now, ever since we came back to work the day after New Years, she walks past me without saying good night - at all. At one point I caught her seeing me coming toward her department and she  immediately turned to walk the other direction from me. She kept a bunch of silly little drawings I used to make for her over the last couple of years, and I noticed they're all gone now.

I feel like some super petty stuff is going on here that I don't know about, and I'm rolling my eyes inside. This is a woman in her late 30s. I'm not even interested in asking her if she has a problem with me anymore, because I've done my part and been civil. I've come to terms with the fact that we're just going to be coworkers, but this childish stuff is getting a little annoying and hurtful and even making only being coworkers a little difficult - I tried hard to get back to coworker mode with her and now that I feel I have a grasp on things getting back to normal, this happens. I get along great with all of my coworkers but I don't want to ask them if she said anything because I really don't want to drag anyone else into this.

Do I just continue to treat her like another coworker, as I've been trying to do?  Or should I just say screw it and completely ignore her too?

Edited January 3 by Seymore

[MsJayne]

My take is that she expected you to fall at her feet, you were supposed to declare undying love when she expressed second thoughts about her engagement, and when you didn't she cracked the darks. When she was discussing her doubts about her fiance you should have taken note of the behaviour more than the words, it's highly inappropriate and tells you that she has no integrity, she's disloyal and disrespectful. Likewise with the flirting with you, this woman has a partner so why was she carrying on like a teenager with a work colleague? For her to start being rude and sulky towards to you within the workplace context is just so out of line and smacks of her bruised ego. My advice is to keep all of her flirty messages in case you ever need evidence of who was driving the inappropriate exchanges, and to be grateful that you never went beyond flirting because she sounds like the type who would accuse you of harassment if you got on the wrong side of her. Just continue to treat her like any other co-worker, be polite, never give her a reason to start knifing you in the back to other colleagues, because she sounds like the type who would do that. 

[Seymore]

16 minutes ago, MsJayne said:

My take is that she expected you to fall at her feet, you were supposed to declare undying love when she expressed second thoughts about her engagement, and when you didn't she cracked the darks. When she was discussing her doubts about her fiance you should have taken note of the behaviour more than the words, it's highly inappropriate and tells you that she has no integrity, she's disloyal and disrespectful. Likewise with the flirting with you, this woman has a partner so why was she carrying on like a teenager with a work colleague? For her to start being rude and sulky towards to you within the workplace context is just so out of line and smacks of her bruised ego. My advice is to keep all of her flirty messages in case you ever need evidence of who was driving the inappropriate exchanges, and to be grateful that you never went beyond flirting because she sounds like the type who would accuse you of harassment if you got on the wrong side of her. Just continue to treat her like any other co-worker, be polite, never give her a reason to start knifing you in the back to other colleagues, because she sounds like the type who would do that. 

I actually don't have the messages from her, because she requested we move our talking over the summer on to Snapchat. And now what you're saying makes even more sense because Snapchat texts expire after 24 hours.

Now things are looking extra shady.

[the searcher]

She showed that she was untrustworthy by flirting with you while she was engaged. Maybe she did it when the relationship was strained, like during a fight, for example. Either way, she seemed happy that you had shown interest, which boosted her ego. Be professional, be careful, and prepare for a period of awkwardness between the two of you.

[Esteban]

She seems toxic and being in a relationship with her would likely be awful, I would keep it to hello, goodbye, and needed work communication. If at some point one of you leaves the current organization, I would cut off all contact with her at this point forever.