Special cases of intimate relationships are with your parents (unequal when you are a child, potentially equal when you have grown up), with your siblings, and with your therapist (if you have one).
Parents and siblings
Almost everyone will have had some intimate relationship with parents and with siblings (if you have siblings). If unusually it is not with parents, there will have been some other “primary caregivers” in your youngest years. If as an adult your major intimate relationships are still only with parents and / or siblings, this seems to be something to query at least: you may be overdependent on your family, and your life may as a result be impoverished.
Mature adulthood can be defined as the ability to have, and the reality of having and maintaining intimate relationships with other adults than your family of origin.
The therapeutic relationship
Psychotherapy, and your intimate relationship with your therapist, have a similarly exceptional status as intimate relationships with your family of origin. Therapy can do major and transformational things, but therapy is not a purpose of its own, and cannot replace intimate relationships in your life outside therapy. If it would replace them, you would be overdependent on therapy – just as an adult who does not separate him - or herself from their parents and / or siblings is overdependent on their family. Temporarily (and at the extreme this might be for many years) therapy can and may need to be extremely important and central, and may for that time be the closest intimate relationship in your life. But this must be carefully watched by yourself and by your therapist; it should not last indefinitely.