First off, have you talked to him about his porn consumption and your concerns? From the sounds of it, I am guessing not.
Porn, in my opinion, is perfectly natural. As long as he is not subscribing to child pornography or snuff, then I believe it to be normal. Men typically are more visually stimulated than women. Maybe you don’t go online to look stuff up, but can you tell me every time you have sex with your husband you are actually imagining his head on his body and not Channing Tatum’s (or insert hot guy’s name here)?
I would invite you to explore what your specific issues are with porn. Has it interfered with the two of you having sex? Does he choose porn and masturbating over having sex with you? If so, then that would call for a conversation around why you two are lacking intimacy in your relationship. Then, I could understand that you would feel rejected and replaced. Maybe he doesn’t understand that, and needs to hear it from you.
If you are still having sex regularly (whatever that definition is for your relationship), then I venture to say it is just a fantasy. Fantasies are a normal part of sexuality. He may just be keeping his separate from you and believing the two are mutually exclusive; which they don’t have to be. Some solutions to this might be asking him what he enjoys about what he watches and finds arousing. See if there isn’t a way to become part of the fantasy with him. Would you be willing to watch porn with your husband? There are several companies that specialize in making porn by women for women. Here are some links to suggestions:
http://msnaughty.com/blog/2013/12/18/porn-for-women-retrospective-2013/
http://www.marieclaire.com/sex-love/advice/a509/female-friendly-porn-for-women/
http://www.yourtango.com/2013198616/best-porn-women
Could it be finding out what turns him on and trying some variation of it in your current sexual play? Maybe he finds the typical school girl fantasy particularly intriguing… are you against going out and buying a little plaid skirt with some stockings and Mary Janes to “play” with your spouse? Integrate yourself with the fantasy and perhaps you will feel less put off by it. Maybe you have some fantasies. What if you staged one of yours instead and invited your husband to join you? I’m pretty sure he’d be game to get into what you’re into.
Regardless of the approach you take, communication with your husband will be key. I can understand that telling him this is nerve wracking and very emotionally intense. So, I recommend having this conversation with him not during an already heated moment, but bringing it up when you two are having a nice time and have the time to talk. It doesn’t have to be a fight, either. Try to remain curious rather than offensive. If you really can’t get on board with being part of it, maybe just find a way for the two of you to be in separate ends of the home so you don’t have to be exposed to it.
