In Sickness and in Health.

Traditional wedding vows promise love "in sickness and in health" -- the clear implication being that one is bad (sickness) and one is good (health).  Hard to debate really, we'd all rather be well than sick; but, consider that both are a natural part of human existence and that there are many conditions of health that fall in between the extremes of "I'm sick" or "I'm well." 

Further, sickness is not customarily a choice and can set up a burden factor in the relationship.  The healthy partner can feel burdened by the unwell partner.  And the unwell partner can be burdened by his/her own unwellness.  So, rather than set up this framework of good vs. bad right from the start of a marriage, why not consider tweaking the language to support the natural ebb and flow of the body's condition and to support the aging process (growing old together) which naturally gives way to less than optimum health. 

Here are two alternatives to the traditional phrasing that might get you thinking:

We promise our love and devotion to one another "in all conditions of health"

or

"through the ebb and flow of the ever-changing condition of our bodies and minds."