1 Corinthians 7:27-28:

Art thou bound unto a wife? seek not to be loosed. Art thou loosed from a wife? seek not a wife.
But and if thou marry, thou hast not sinned; and if a virgin marry, she hath not sinned. Nevertheless such shall have trouble in the flesh: but I spare you.

See also:

Unforgiveness Is Itself a Forgiven Sin, So How Could It Hinder My Healing?
Am I Sick Because God Has Turned Me Over to the Tormentors Because I Didn’t Forgive Someone?