I am very unhappy with my life right now. Someone with serious good advice please help me!?

I have recently gotten married to my girlfriend of 2 years. A couple months before our marriage, the relationship was rocky but when she got pregnant we got married because I thought it was the responsible thing to do. It's hard but I am able to live with her. (Barely). Mostly because her personality has changed since our engagement. The real problem is that recently I have become very attracted to her younger sister with whom I could never have a relationship with, and I my ual attraction to her has diminished. with my wife before we married was rarely very good because she is inexperienced, but I loved her more for her personality, not just her looks or for . Is there a possible way for me to hypnotize myself so I don't have a crush on her sister and I find my wife ually attractive again?