People who are trained as counsellors often think they can counsel anyone including their spouse, children or other family members. This is often not true. Why?
A counsellor does not start with having a specific goal in counselling. They do not have an interest in the outcome of the counselling. If the client comes with the idea of wanting to break from the marriage, the counsellor does not have a fixed idea that they should at any cost not allow the marriage to break and neither do they have the idea that divorce is good. A counsellor does not think one is better than the other. A counsellor role is to help the client make whatever decision they want to make with full awareness of the consequences and not make a decision when their emotions are hijacked. At the end of the sessions, if the client wants to continue to work on the marriage, the counsellor helps with that. If they want to break the marriage and live independently, the counsellor helps with that. The counsellor does not favour one decision over another.
The reason why as counsellors we cannot counsel our spouse, children or other family members is that the decision they want to take may affect us and we may directly or indirectly influence that decision through our counselling. When we try to influence that decision because it serves our purpose better, we are not doing counselling but advising them to take a decision that we will be comfortable with. We have a role to play as a spouse, a parent, a child, a sibling, a friend etc. We all need to play that role. That role will clash against the role of a counsellor.
If my spouse comes and says she wants to quit her job, I may not be able to view that dispassionately as her decision may affect me. I might think of the financial situation if she quits working and advice her accordingly. This may not count as counselling as I am pushing her towards a decision that suits me.
Counselling has to be done by an external person who has no particular interest in the outcome of the counselling process. They are okay if the client wants to stay or leave the job, be in the relationship or get out of it, study further or take a job. You can still counsel your spouse or family members on issues that do not affect you. But this does not prevent us from bringing the counselling attitude (listening fully, be non-judgmental, have empathy) to our close relationships. In fact, that attitude will deepen our close relationships.