I feel your frustration here... It takes so much time and effort to get a POT that you really like to go BCD. So when that BCD fails to deliver on your expectations (I mean this isn't even close!), you must be disappointed.
Now let's review the key fact presented: She has clearly stated her sexual limits, and they are far less that your desires. Can you change her limits or expectations? The likelihood is extremely low. If it's even possible, it will likely take an unreasonable mix of time and/or money. Almost ANY SB will do you raw, with anal, CIMWS, etc. at least once if you offer enough inducement. Let's test that claim with an extreme case: If you offered her $1 million in cash, do you think she would accept? How about $500k? $100k? etc., There is a lower limit of what she will accept, but why bother trying to find it? You can spend that time and a fraction of that $100K looking for a POT that likes sex - all kinds of sex.
Next: I'll take this opportunity to review one of the big lessons learned in the Sugar Bowl: All arrangements end. It is inevitable. When you find yourself contemplating extraordinary efforts to extend an arrangement, it's like spitting into the wind; you're going to get soaked and not in a good way.
Once have realized that it's time to end the arrangement, then yes, text is the way to go. Ok, it sounds impersonal, the typical dickhead move. But I contend that if you want to break up face to face, you need to commit to paying her allowance one more time whether you go BCD or not. And texting does not have to be rude. You can compose an honest, though gentle, message to let her know it's not working out. She may want to reply, she may want to call or see you, or she may block you. But at least you were mature and honest. Finally, ghosting is the true dickhead move. She will have no context and could misinterpret your action in lots of (potentially) bad ways. Best to let her know it's over (at least for now) and give her the clarity she needs to move on.
Finally, how to avoid this going forward? There is no 100% solve here. Consenting adults can ALWAYS revoke consent, even when your dick is hovering a half inch from heaven. But talking in advance about what she likes and dislikes will help. For me, I have a rather specific discussion before we even talk about allowance. There are certain must-haves for me, as well as additional preferences. So my risk of getting disappointed is lowered, but never eliminated.
For those who prefer to skip the M&G and close the deal to BCD asap, (a valid strategy for many with what I suspect has a high close rate - but a strategy at which I suck), there may be a higher risk of being disappointed, unless they can find a way to get some level of assurance of what to expect.
Please let us know how you fared. We would all appreciate the opportunity to learn from your experiences.
Life is good
The Cat