Hi, I'd like to help you with your question.
Anytime a person goes outside of their marriage and has a relationship with another person, it is cheating. This relationship can be based on texting, talking (sharing intimacy), sex or other contact.
The only time your husband should have contact with the opposite sex is if you are included. By that I mean if he is friends with a female, you must be included in that friendship. You should never be lied to or deceived about any contact he has with anyone of the opposite sex. If he lies or hides the relationship, it is cheating.
Your husband also should not be texting this person, at all at anytime. His primary relationship should be with you.
Has he admitted to this relationship? Has he taken responsibility? He needs to do so in order to save your marriage. These are his actions so he must take the blame and begin to work on rebuilding the trust in the relationship. To start, he should have no more contact with this person. He then needs to take the initiative and work with you to repair the damage. His communication with you must be open and honest. No lying, contact with females (other than work relationships) and he should go to counseling with or without you to deal with why he had this relationship outside of his marriage.
You mentioned that you both saw a counselor. Did it help? If not, you might want to see another. Finding a good counselor that you click with can sometimes take a few tries, just like it does when you try to find a good family doctor. You can search on line at http://therapists.psychologytoday.com/rms/. If your husband doesn't want to go to counseling with you or feels he needs to see one on his own, then you should see one as well. It will help you work on the feelings you have about the betrayal.
There are also some books that may help you:
Infidelity: A Survival Guide by Don-David Lusterman
Not "Just Friends": Rebuilding Trust and Recovering Your Sanity After Infidelity by Shirley P. Glass and Jean Coppock Staeheli
My Husband's Affair Became the Best Thing That Ever Happened to Me by Anne Bercht
You can find these on Amazon.com or your local library may have them for you.
Keep in mind it is very normal for you to feel betrayed. You had the idea of a good marriage taken away by what your husband did. Be good to yourself, give yourself time to cope, mourn your loss (of the relationship you had before the affair), and keep talking to others. A good counselor, your pastor and family and friends can all help you work through your pain and your marriage.
I hope this has helped you,