I don't think your surgery has had anything to do with it. Men are given what they have and there is no more. I would say that your weight could be the issue if it keeps you from getting very close to your wife. If that is not it, then you may have to learn to please your wife in other ways. FYI penetration is not generally what brings a woman to orgasim in first place.
It’s been said by many women that the perfect penis is 2 inches long and 4 inches wide! This is because the inner two-thirds of the vagina has very few nerve endings, and for most women, it’s only the outer third that’s sensitive. And most women don’t orgasm from penis-vagina sex (p-v sex) alone, so don’t put that kind of pressure on yourself. Since your wife has pain issues, you might try some positions that maximize stimulation for her and minimize potential pain. Try the rear entry position, which results in deeper penetration. In this position, either of you can also manually stimulate her clitoris. Also try the “scissors” position, side-by-side facing each other, with one of your legs between hers. And don’t forget that many of us also enjoy being touched on various parts of our bodies during p-v sex. If this is something you’d like to explore, don’t be afraid to tell your partner. And please don’t forget about kissing! Many people are turned on by deep, soulful kisses during p-v sex. Look at this as an opportunity for the two of you to get creative and have fun! Dr. J