Is it possible for major depression to cause one to loose interest in a marriage they otherwise liked? or lack of energy to invest in it?

Yes: Major depressive episodes can occur in (unipolar depression) major depressive disorder or in bipolar disorder (bipolar depression). A hallmark symptom is diminished (or absent) interest/pleasure in all (or almost all) daily activities. This can include diminished interest and hence isolative behavior from family and friends. Further compounding this difficulty is a potential experience of fatigue.

Partners in Agony: While depression does not lead directly to divorce, the consequences of not addressing the problem will. For example, depression can lead to a lack of intimacy and communication difficulties. When these experiences occur, symptoms will likely worsen and result in partner isolation, affairs, and/or divorce.