How do you know he doesn't?
I look at porn (though I prefer the term erotica. It covers a wider range of materials), but when it comes to fantasizing my brain brings up my husband. Different characters are all aspects of him and his personality. He is what truly turns me on. The erotica is for ideas and background material.
My husband looks at porn and reads erotica. It doesn't take anything away from what we share.
In all of your trying to please him, have you talked with him. Do you share your fantasies with him?
As much as I am okay with erotica and don't mind my husband flirting, interactive sites are a very different matter. You should not put up with that type of behavior and he shouldn't have been involved in it. However, I would worry about it happening again. He probably now understands that it crossed a major boundary line.