Attempting to teach your wife, friend, sibling etc can create friction and adversly affect relationships. If you wife truly wants to learn and isn't trying to get some attention and affection (there is nothing wrong with that), find an instructor for her and then lavish her with your attention and praise. If it's your attention she craves then use the guitar to create the intimate contact putting your arms around her to assist fingering and strumming. This is not the methodology a guitar instructor employs. You may not get results in her learning to play but you may get results in the area of intimacy. Don't expect that your wife will learn from you. When she is truly interested she will seek instruction from a teacher who can coach her. You can assist with searching for the proper instructor and encourage her practice and praise her performance. Once she has the basics there can be a lot of intimate fun playing guitar together. Instruction takes paitence and the student has to be open to accept feedback. Relationships make this difficult as you want your wife to progress but may become impaitent with her progress making her over sensative to your feedback.