I often explain that "polarized couples" (one wants to 'talk it through' and the other hopes it 'goes away' for example) find their marriage grinding to a halt when they believe they must "work on the relationship?'

Here are some difficulties typically experienced when a couple commits to "working on the relationship:"

1. "Working on the relationship" often implies that each "should or must" act, feel and think particular ways to make their efforts successful. A "should" sets one up for failure and disappointment, for no one ever fully acts, thinks for feels as they "should." An atmosphere of effort and grinding it out permeates the couple. And, each holds his/her breath, as they both believe that failure follows the next interaction. Talk about pressure! I assume you want a different environment created in your relationship.
2. "Working on the relationship" for a huge percentage of the couples I encounter means being "nice," accommodating the other and being on your best behavior. Conflict is seen as a catastrophe. Such a strategy, in essence, obscures and clouds the truth. The truth, which sets a couple free, is relegated to the background and buried under the surface.
3. "Working on the Relationship" often means trying to find a "middle ground." There must be "something in common" that holds the couple together and make it better. Well, maybe there isn't any "common ground!" And, just maybe that is good. Perhaps the differences, the extremes, give the couple fire and passion and create, together, that which each, at one level, is looking for.
4. "Working on the relationship' often means working hard to meet the needs of the other. I "sacrifice" my needs, or at least put them on the back burner, and intentionally go about "making my partner happy" by attending to his/her needs. This may work for a period of time but resentment at some point emerges since one or both believe that the need meeting is not being reciprocated to the degree he/she would like.
5. "Working on the relationship" often is thwarted because there is not enough depth. Individual differences are not pursued with a curiosity and intensity that allows for maximum growth of the individual and therefore couple. "Issues" are not torn apart, looked at, marveled at, appreciated and seen as a resource for further self exploration and self disclosure.
6. "Working on the relationship" often comes up short because a couple easily reverts to old patterns. They begin to "swirl" in the old communication patterns and ways of thinking, feeling and acting. When lacking adequate exploration of differences and avoiding conflict the couple easily slides back into that which was familiar, not pleasant or comfortable, but certainly known territory.

I'm assuming you don't merely want to "work on" the relationship, but you want a total overhaul. After all, the infidelity crisis does provide a great opportunity to recreate and redesign the relationship, now that you are wiser.