Check your diet. If you're not eating right, your mind and body are not functioning they way they should.
Check your activity level. If you're not getting exercise, your mind and body are not functioning they way they should (even at age 26).
If you're eating correctly and getting exercise and still feel this way, get yourself to a doctor. There may be other problems between you and your wife, but diet and exercise will get you to the point you can deal with them.