After A Brief Illness?
Where I'm from, when someone dies suddenly...they say "he/she died after a brief illness". When in reality, the underlying cause is an un-diagnosed or disregarded ailment.
In the same vein, people do not just end their marriages after a little argument...the crescendo is what everyone sees, but it builds up from

disregarded signs and warnings.
Moments of ignoring each others feelings.
Periods of pretending that all is well.
Dealing with trivialities and hoping that the real problem goes away on its own.
Denial
Failure to deal with small issues till they gather mass.
Abuse of a spouse's good heart/nature.
Wanton disregard for the sanctity of marriage.
Abuse of forgiveness.
Continuous physical and emotional abuse
Failure to seek help when it is obviously needed.

Those that know the importance of good health do an 'annual physical' to check that all is well and if there's an issue, they can tackle it ASAP.
Married people with a view to having a happy home/marriage should also take time to review their marriage from time to time...

Start by being doubly sure that all is indeed well (many times we camouflage potentially volatile issues with activities, 'busy-ness' and the mindset that 'if it ain't broken, don't fix it')
Ask your partner what they think of the relationship...ask if they are getting all they want from it and tell them your opinions as well
Based on your findings, work out a plan to fix the issues raised...don't just ignore them or see your partner as being petty. It's like ignoring an open wound.
If there are bigger issues...talk about them
Know what causes the issues
Look for trends and patterns
Look beyond the surface, dig deeper
Know what causes what and what aggravates what
Deal with it...if it's beyond you, seek help
Learn to nip issues in the bud (this stops the spread of its poison in your marriage/relationship)

So according to 3rd John 1:2
I pray that you may enjoy good health and that all may go well with you, even as your soul and marriage/relationship are getting along well in Jesus' name