love gives satifaction with the partner
lust wants change of partner
love accepts reality
lust depends upon the imagined charms of the partner
when faced with problems in marriage seeking someone other than the partner appears to be an alternative but does not solve the problem permanently

it is a desire to get away from monotony of the routine
such brief relationships is more common
but seldom lasts long
ultimately true love triumphs hence all attembts shoud be made to repair a failing relationship