As husband or wife, when you discover that you don't have interest of sex with your spouse again, it's not a sign of being spiritual but being spiritually sick. You know why? After the devil waits to make you completely lose your romantic interest and attraction towards your spouse, he will then connect your affection and attraction to someone outside, and that is the beginning of a total downfall.
If you have lost your sexual and romantic feeling towards your spouse, it's a matter of time before lust towards someone else outside will come and before you will fall into the trap of adultery.
So before your affection and romantic feeling towards your spouse get lost, you better get it back and refuel it, before the devil replaces your real love towards your spouse with a lust towards another person outside. Those who go down the road may not be able to tell the story.