Are you seeing your therapist by yourself or just with your wife? Sounds like seeing her by yorself may be more helpful at this point. This is not the time to stall and not be open with your therapist about your feelings. She may even suggest you see a psychiatrist or doctor for some anti-depressants.

IMHO It is healthier for the child to have a positive relationship with two parents that live separate from one another than two parents who are distant and/or argue constantly. Once my ex was out of the house, I could see the positive impact it had on me and the kids. It was like someone had opened a window and we could finally breathe.