It is written in A Course In Miracles, "To believe that special relationships, with special love, can offer you salvation is the belief that separation is salvation." T-15.V.3:3 It is not the job or purpose of a relationship with another person that that person make you happy. That person is having a hard enough time making herself happy, let alone taking on the burden of making you happy. Each person must ultimately take the responsibility for his/her own happiness not put the responsibility for that on somebody else. This idea that someone else will make you happy, is suppose to make you happy, is the path to hell.
The spiritual answer to the dilemma is that we are suppose to love everybody unconditionally. The definition of the At-one-ment is when everybody loves everybody all the time. That is heaven. Anything less is hell. Unfortunately, most of us operate on the level of conditional love. I'll love you if.......
It is a challenging thing to love someone unconditionally and yet it happens, it can happen, when we ask the Holy Spirit, the Spirit of Live, our Higher Power for help. In that holy instant when unconditional love occurs we have created heaven on earth and experience bliss.
Focus on your own growth and happiness and forget this idea that someone else will make everything okay for you. This is looking for love in all the wrong places and true love is not to be found in special relationships. Special relationships are part of the curriculum of life to help us learn about love, what it really is, and your disenchantment with the relationship with your wife is a golden opportunity for you to look inward and rise above your own desires for ego gratifications. The spiritual rewards of this path will far outweigh the temporary high of a new infatuation.