God is both Love and the Righteous Judge. He is seated for life, and for Him that is forever.
Irregardless of His unfailing mercy, love, and grace, He must, as the Righteous Judge, judge willful sin.
Willful sin removes the cover of grace that way too many use for a licence to live a sinful lifestyle.
Adultry holds the grounds for divorce. So too spiritual adultry tears the fabric of covenant grace.
God is merciful and compassionate but it is foolishness to push it.