Relationships start out full of hope and expectation but can end up mired in varying degrees of disappointment, resentment or recrimination. When things go wrong, a lot of difficult feelings get stirred up and things get said or done that are hard to take back. At that point, the focus is often on the other person and their shortcomings.
But a couple is a co-creation; both people have a part to play in what happens in a relationship, sometimes in ways they are not conscious of. Couple therapy can help you to explore how you have arrived at your current state and provide a safe and non-judgmental space to begin to think about how things might be different.
Therapy can invigorate a stale relationship by improving intimacy and communication. If it really does feel like the relationship has no future, therapy can be useful in enabling a couple to bring it to a more thoughtful end.