[Anal] My girlfriend wants to REuse a strap on on me.

I shared with her that I like getting my ass licked and fingered and that light humiliation talk excited me. To my surprise she loved the idea and we had a great time.

We usually have dinner at her place every tuesday and then have sex. That day (so 3 days ago) she had texted me all day long about a present she bought me and how we were going to have so much fun. I figured It was sex related and was pretty excited for what was to come.

That night the atmosphere was great, she had cooked a great meal, we'd just finished and I was eagerly awaiting my present. She gets undressed, does a little dance (you might think I'm putting too much detail here but this is to give you the full environment in which my decision was made) and gives the present to me. A HUGE strap on and plenty of lube.

As I look up from the present to her face I see her smile with excitement. It was such a pure and perfect night that I did not want to ruin it. So I went with the flow ...

Of course as I suspected I hated it. But I still did not want to ruin the night. She mistook my moans of pain for pleasure ones. When I asked her to slow down she thought it was because I wanted to appreciate it more. Everything I did and say she managed to misconstrue it as me loving it. She goes at it for fucking 20 minutes (why would you even want to do that as a woman blows my fucking mind where's the fucking pleasure) all the while calling me names and eve fishooking me from time to time. IT WAS INSANE.

I managed to survive and tell the tale. I'm seriously hurt (no bleeding but it itches all the time) and have got an appointment to the doctor's scheduled.

Heres the problem, she wants to do it again !!!

She sent me a message saying that she was so scared that I wasn't going to like it and how happy she is that I do. How do I literally not get fucked next tuesday ? I'm not going to tell her that I lied and deceived her she has major trust issues and that will hurt her too much.

I've been racking my brain but I can't find a good reason. I could tell her she tore something in there and that I've made an appointment with the doctor and that HE says I can't but asses heal right ? What then ?

PLEASE HELP.

TLDR: Told my so I like assplay, she went and bought a strap on and fucked me with it and she wants to do it again. What long term excuse can I use to not get fucked.