Low sex drive, low or no libido, erectile dysfunction, or vaginal dryness is something that affects thousands of people - including LDS couples. This clip I found has some helpful information. Please check it out and see if this applies to you. The marriage you save may be your own.
If you or a loved one is suffering from depression, bi-polar or other psychological debilitations, I believe this is important to know when considering presented with psychotropic treatments.
Ask your physician what your options are. There are newer treatments (including natural supplements) that can be effective without affecting your ability to enjoy full marital intimacy.