If I am having trouble in my marriage is it better to see a therapist or a counselor? Whats the difference?

Connection. There is no significant difference for a patient. What makes a difference is how well you connected to your therapist, i mean you trist your therapist, you feel understood.
Therapist/counselor. Technically, a psychotherapist helps a person (or two people, as a couple) change how they think or feel. A counselor "counsels", that is, gives guidance, advice, or encouragement to help people through a difficult situation. In real life the roles of therapist and counselor often overlap partly, but you can still choose which emphasis you want.
No difference. There is no difference between behavioral therapist or a counselor. Some of those may be medical social workers and some may be licensed psychologists, but really therapist and counselor are often used interchangeably. You want to find someone who is specialized in marital counseling, though.
Therapist. Both therapist and counselor are really generic terms. Find a "licensed" mental health clinician, such as a licensed psychologist or licensed social worker who has had specific coursework and/or training in marital counseling.
Mariage trouble. Divorce lawyers told me at least 50% of divorce can be avoided if all couples see therapist-counselor-psychiatrist before making decision to quit.