Well, I’d take either but my preference would be yours (on the right) and simply because of the head. I love uncut cock and I’m not sure if you are or just him but again, the head of yours is what draws my attention.
You look to be thicker and a tad longer too, that may be why she enjoys you over her husband. The guys my wife has slept with behind my back, they’ve all been lighter weight than me, so they don’t have a pudge hiding their cocks. They’ve all been a bit longer anyway, pudge or not.
I’ve said it before though, if she loves you then it doesn’t matter what size you are IF there is also an attraction. True, most women will enjoy a longer cock over a shorter one but they’ll enjoy sex with you if they love you and are attracted to you. Regardless.