Is He/She Cheating On You?

He/she moves away from me and then has a casual quick, witty repartee with the server.
The person I’m with completely ignores me and starts talking straight to the server. It’s like I’ve completely disappeared.
Well the waiter/waitress takes our order and then goes away. But when I mention how good looking our server is he/she doesn’t disagree with me.
Oh well, we’ve never actually been to dinner together, but we did once see each other when we were out at a restaurant and he/she didn’t really acknowledge my existence when I said hello.

Usually in a couple of hours, but this person used to respond right away.
A long time. Some times never.
I’ve only sent this person like one or two text ever, so it’s hard to really say there’s a pattern for response.
I don’t know. I guess he/she writes back within the hour.

The person has the tendency to ignore me.
Well, I won’t always go up to the person when he/she is in a group, but if I do he/she will generally say hello.
He/she will usually say hello and then wrap his/her arms around me.
The person will sometime acknowledge me, depending on who he is with at the time.

I’ll typically say hello when I see her/him in the hallways.
We’ll talk for an hour or so on IM some times, but it’s really hard to get this person on the phone.
Well we used to talk on the phone, IM and text all the time. Now it’s a miracle if he/she responds to a single text.
We talk on the phone for at least an hour every night. We’ll also text and IM throughout the day.