Is cyber cheating

[cadence]

She doesn't think it's cheating so she will not discuss it with me.

I think that now you have a bit of a problem there. You "believe" that she has cheated. She doesn't think it is cheating.
You have asked us all a question to which you are going to have many different answers to because we all have varying opinions. Only you know how you feel and why you feel as you do.

You both need to discuss this without having any accusatory feelings towards each other.
You need to find out why she has done what she has done, and keep an open mind.
She in turn will also have to be able to understand why you are upset.
Disscussing the issues camly and openly, may be able to help you both work this out and be able to come to what you are both willing to do next.

If you both continue to harbour bad feelings and refuse to talk, it will only lead to more deception on either side.