Relationship therapy is not a panacea
When do couples reach for couples therapy? Often when it is already too late. It is better to go to therapy when problems persist. Because it is on the late side, you could say that the damage has been done unnecessarily. Had there been earlier intervention, you could have prevented it from having a greater impact on the relationship.
Especially when we talk about infidelity, a lot has been damaged in the trust which causes an attachment problem. It takes a lot of time to survive this as a couple and the question is do you get that time or is the decision made to break up. The pity is that both partners did not go to therapy so they were not able to learn from the mistakes in the broken relationship.
If one goes into a new relationship too quickly, the problems from the previous relationship quickly resurface resulting in regret. In any case, you learn a lot about yourself in the relationship therapy where it is assumed that you also want to apply this in your life.
New is the hybrid model where you mainly work on yourself and possibly with the support of a relationship coach. This can help clarify the therapy, but by and large you do the therapy yourself to be ready for partner conversations at a later stage.
The partner talks are honest talks that ensure that all pain points are on the table. This can be very hurtful and confronting, but it is the mirror that is held up to you that allows you to acknowledge that both partners make mistakes. Not blaming, but not trivializing either. This is most problematic with a detached partner who does not find recognition with the partner, which only increases the separation.