The basis of any good relationship combines a large helping of compatibility with enough love and compromise to get through most issues, so working it out when there is a disagreement might be possible for a couple. What they see as a mountain to climb could be nothing more than a bump in the road, but their emotional involvement could make their vision hazy. If they are determined to keep their relationship intact, they might consider professional help. Learning how to compromise within a committed relationship is not always easy, and a counselor might be able to help them see what they need to do.
Couples almost always find there are issues within their relationship, but learning to work through them can be a steep hill to climb. They will need to get past the surface disagreements to discover what is really bothering them. It could be that they have fundamental disagreements on important life questions, or they might find it boils down to who is in control of the relationship.
Using a professional to help them sort through their issues has the advantage of a neutral party, so this should be a step to consider when they find compromise is not working for them. They might still love each other deeply, but that will be no help when they head out to find lawyers for a divorce. Taking as many measures as they need to settle their differences could help their relationship immediately, but it could also keep them together over the long run.
It is not always easy to work within a relationship when two people find common ground is lacking, but taking the time to work out their issues could set them up for a good life together. Difficult decisions can separate two people, but it can also draw them closer than they ever thought possible.