To be able to share anything with your spouse/partner should be guaranteed. However, when your relationship is not going well, it may be not the safe haven you expect.
Sometimes, it is a matter of rebuilding communication and commitment to improve the relationship.
Sometimes, it is a matter of finding ways to part amicably for the sake of the friendship and family.
Therapy can help couples grow together through the years, unite blended families, or assist separated/divorced parents in co-parenting.
The goal is not to take sides, it's to help everyone reach a more peaceful resolution.