Lucky,
A good therapist should be able to help the couple see their needs clearly and help each side to hear the other and explore solutions to their problems. Their job is not to control people only to reveal what is going on and help them formulate a plan that leads to a healthier relationship. Whether that relationship continues to be marriage depends on many things.
Sometimes people change or give up too much in a relationship. The marriage may or may not continue, but an amicable divorce with two supportive parents now happier alone than they were together can in my book be much better than two unhappy people giving children a very poor idea of what love and married life entail. Children know when mom or dad is not "okay." If they are raised to see marriage as a sad place of unhappy compromises, they may accept too much compromise in their own relational lives. I don't think seeking good professional help is ever a bad thing.