It takes some gentle persuasion with enough preparation to get her to try it. I wish you both luck. Here is my story.
I understand her reluctance and I understand your desire. I was completely against the idea because my first husband tried to dry r**e my butt. It was so painful and it made me bleed. My second husband was a good sexual partner. We had been married about 10 years when he got more adventurous while I was drunk and less inhibited. He started by using his fingers in my pussy then worked his thumb into my butt to loosen things up. He was gentle with me because he understood my aversion. That turned me on too. That was all for the first time. A few days later I was in a deep sleep after we had been drinking most of the day. I was mostly on my side with my back to him, then he slid my panties down and put some lube around my anal ring. I sort of became aware of him working his finger inside me slowly when I started to respond and began pushing back against his hand. He talked to me gently and coached me to relax and work my ass for him. He praised me the whole time telling me to be good and enjoy it. By the time he had two fingers in me I was working back and forth almost to orgasm. He said "you want it don't you?, tell me." At that point I wanted him to take me where I had never been emotionally and sexually. He gently put pillows under my stomach to get my butt into position and with both of us lubed he gently worked it into me one inch at a time. About half an hour later I was saying things I never thought I would say. I said I'm a bad girl, do it baby make me pay for being bad. All the while he was saying things like "your a bitch aren't you, beg for it, now be a good girl and beg for what you want".
He was g*fted with a good almost 8 inches so I couldn't take all of him the first few times we did it. I admit I was sore after and it made me walk kind of funny and even that turned him on.
