I'm upset about my sex life
What's wrong with your sex life?
I don't feel attractive when I'm with her due to my weight gain
Lots of people gain weight, especially during this time of the year. You could come to the gym with me if you're looking to improve yourself?
I can't be objective when we have sex. She's always looking at me, either hoping it won't happen or ready to go.
I think that you are being a bit too hard on yourself. Have you thought about speaking with her about your feelings?