I don't think anyone could handle driving and fighting for eight hours. That's just a terrible situation. I think it's also terrible for your wife to emotionally distance herself from you. That's not a healthy relationship even if you didn't have bipolar. You say she has good reason to keep her distance, but what could that be?

One reason to stay alive is that things don't stay the same. Although things are not good right now, they do change. That can be hard to believe when you're depressed. I think you need to discuss things with your wife. Has she ever spoken to your T or pdoc with you? I think your relationship needs healing. You may be disabled but do you have any hobbies or talents that you can start a hobby? Having a purpose is key to healing. Maybe you can't have a traditional job and earn a wage, but that doesn't mean you can't find meaning in another way.

Hang in there, I know it's hard.