Sounds like there wasn't enough discussion about expectations and what is "safe" versus "unsafe" to you and also to your partner.
I don't perform oral sex with barriers. Though there is still risk, it is lower than that of unprotected PIV or PIA sex. However, any partners I have are aware of this prior to engaging in sex or other fun stuff like that, and have the option to consider me an unsafe risk and choose not to have sex with me.
I also don't require proof of a clean bill of health from folks I have oral sex with; if I trust someone enough to have their privates in my mouth or mine in theirs, then they're someone I know and trust incredibly well.
Then again, I can count on one hand the number of people I've provided or received oral sex with in my life. There is currently only one person with whom I am having oral sex regularly, and only one other person with whom I would be willing. Oral sex, for me, is a much, much more intimate and trusting act than just plain ol' PIV. I don't have oral sex with just any partner, whereas I'll have PIV on a first or second date in some cases. I do use barriers for PIV or PIA, always, with every partner, no exceptions.
I do not consider myself fluid bonded with anyone, despite the fact I engage in unbarriered oral sex with folks. I consider that to be an acceptable risk, for me. Of course, YOU have to decide what is an acceptable risk FOR YOU, and if you feel that unbarriered oral sex constitutes an unacceptable risk, I think that's perfectly reasonable. But your partner(s) need to know that, too. I suspect that your partner, like me, just considers oral an acceptable risk, since the risks are appreciably lower than those involved with PIV or PIA. I think this is an easy misunderstanding to have made, but it could have been avoided by extensive discussion on what "safe" means to her, and to you. Make sure your definitions mesh.
On the other hand, unprotected oral with a stranger met for a second time? Not in my future. Would that, to me, constitute an unacceptable amount of risk for a partner? .... Maybe. I'm not entirely sure.