Can't stop being jealous of co-worker crush talking to other guy

So I've had this crush for a while. We got pretty close, messaging all day via skype in work. Then i noticed things started to change when she started to talk to my friend in work. She stopped initiating contact with me and becoming less enthusiastic when answering me. She is now very interested in my friend, i can see them looking at each other all day over the monitors, laughing etc, just like the way we used to do.

Basically she has shifted everything we had from me to him and now doesn't bother with me. She will talk fine to me face to face, very friendly and polite. But when it comes to messaging, she has completely cut me off and moved on to another guy. I even asked her if i had done something wrong. She said she was just busy with work. Even though she knows i can see her talking to this other guy pretty much constantly for 8 hours a day....

Its driving me insane. I get so filled with jealousy and anger. I know i need to forget about her and move on but it's difficult when i see her everyday and see the both of them getting on so well right in front of me. I can even hear them typing all day.

I know she has lost interest and found what she needed in someone else, the jealousy is the hardest part. I don't know if i should just ignore her completely, avoid looking at her when i walk past or look up. Stop talking completely? I know i will lose her completely, but i don't know if there is any other option. I always feel like i'm competing with this other guy and coming off second best, it makes me feel pathetic.

So should i completely ignore her to get over her?

FYI. She has a long time boyfriend outside of work

Thanks