(1) Work starts to 'pile up'. More overtime, meeting of clients
etc.
(2) Use 'what-if'. Tell your hubby abt this 'friend' who betrayed
his wife's faith. And specially mention if you were 'his' wife,
you'd kill 'him'. Add some description to the killing.
(3) 'Cos it is thrilling? Men get bored easily.
(4) Sit down, have a heart-to-heart talk with him. Find out why his
heart changed towards you. Work to rectify the problem. Who knows,
it may just be a passing fling.