I am a guy. Most guys when they look at porn are looking for variety, something different to spike their imagination. The brain is the biggest sex organ.
Just about any woman can be sexy. Sexy is attitude & confidence and that sometimes comes across and onto the camera. BBW women can be sexy as hell. May I ask you to take a moment to watch the following You Tube video (pay special attention to both the audience and the judges reactions). https://www.youtube.com/watch?v=DRLf-IepDyU
She is skilled and confident. I wouldn't want to be married to but she is kind of fun to watch.
For myself, when I look at porn (every now and then) it is usually fantasy stuff that I would not want to do with anyone. That is strictly fantasy, no I don't' think I would want to do that in reality, with one exception (oral sex). My wife that I love will not give or receive oral. She thinks it is unclean, unnatural and immoral. I have talked to her about it, tried to negotiate it, our sex therapist tried to talk her into trying it. It is something she is absolutely against, and its her body/mind so I have no right to try to force her.
If your love life is fine, your husband is faithful, don't worry about it. Just give him that look, shake your head and say silly boy, enjoy yourself, but come to bed with me.
In the big picture of marital problems, this one shouldn't score very high.