Let her do you with a strap on and show her how great it feels. That was my wife's reply, ended that discussion.
Well that's a shame. You might enjoy it yourself. Many men do.
You should express interest. Share anything you've found about how pleasurable it can be and remember it could take a LONG time for it to happen. You just need to start slowly and remember that she can say no at any time and you'll continue to make her feel good. Let her explore her fantasies as well.<br />
And yes, as said above, perhaps she'll want you to do it as well. Many men love anal stimulation so don't be afraid of it. It isn't "gay" to like parts of your body stimulated.