I think a good way to deflect from the gay issue would be to bring up the sexual preferences that you said you told her about and she said she wouldn't do. This might make her mad but it might force her to think about whether she's justified in putting such a convenient label on your sexuality. Of course, if your sexual fantasies involve cross-dressing(a lot of straight men have these kinds of fantasies) or anything along those lines this might backfire on you.

Does she know you were viewing pornography? Does she know what kind of pornography you were looking at? I had the gay suspicion about my H for about a minute but spying on his porn habits (some weird sh*t but no boys) pretty much put that theory on the junkheap.

"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver