Hi, I'd like to help you with your question.
If the counselors that you worked with felt that your wife had personal issues she needed to work on, then that might be the best option for your marriage.
The counselors must be seeing something with your wife that makes them feel she needs to be seen on her own. Your wife's past issues can cause her to view things in a skewed way. She may not have the skills to relate to you or to deal with her problems. Often, people who experience abuse or other trauma in their childhoods grow up to view their relationships in the way they were taught. So for example, if someone is physically abused they may be defensive with others. They view others as out to hurt them and willing to be in their space, like their abuser was. So they push others away and put up emotional walls to protect themselves. It worked well when they were being abused but it does not work well in other relationships.
Your wife may also have emotional scars that interfere. She may need to work on defense mechanisms or even work through any emotional trauma she experienced if her parents abused each other or used drugs and alcohol.
One of the issues with your wife's desire to have you in therapy may be that your wife does not see herself as part of the problem. She may be transferring some of her issues onto you. Or she may be fearful of going to therapy alone.
Maybe asking her why she wants you along may help you find what the issue is. If she feels that she cannot go alone, offer to sit in the waiting room. But tell her that you need her to work on these issues so the two of you can have a better marriage.
I hope this helps,