This is troubleshooting at best.
Women will cheat on their boyfriends. It's nature. Boyfriends who are skilled enough in building deep emotional connections, giving the girlfriend enough orgasms (very few men can tell a fake woman's orgasms from a real one and most women fake their orgasms according to several prominent studies), maintaining high sexual hormonal levels, and keeping the romance alive through a consistent emotional roller coaster ride are the ones who can keep their girlfriends faithful and loyal.
Your hot babe's boyfriend has at the very least built enough emotional connections with her to resist your kiss close. But I doubt it if she has been getting enough orgasms that her body needs. This explains your near successful kino escalation. Her guilt won over her libido which roughly translates to:
Deep Emotional Connection > Need for Sexual Gratification
SexAddict911 has offered excellent advice already. Hence, I won't delve on that.
Instead, I will advice you to keep the proximity to trigger her sexual urges again and build deep emotional connections with her. Anchor your wide rapport routines on her childhood experiences. When you find something that sparks her eyes and make her happy go into deep rapport with her and restart your kino escalation.
Remember, to keep a woman you'll need to:
- 1. Build deep emotional connections.
2. Give her lots of orgasms for the oxytocin boost which strengthens attachment.
3. Maintain high levels of sexual hormones.
4. Give her enough of her emotional roller coaster ride (simply known as drama) needs.
I have fuck closed a few girls who never mentioned their boyfriends and some even denied having boyfriends which later turned out to be untrue. This troubled me a lot and so I looked for the scientific basis why. I gave you the why and the how. If you want the scientific journals, just drop me a PM and I'll send some your way when I have the time.

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Approach. Open. Escalate. Isolate
Here are my two essential rules on texting that will save you tons of time and money:
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