The Babylonian Talmud sets forth in Yemavot p.76 A that relations between women are not considered actual sexual relations, stating, "“And even according to Rav Eleazar, who stated that an unmarried man who cohabited with an unmarried woman with no matrimonial intention renders her therefore a prostitute [zona], this disqualification ensues only in the case of a man, but when [the case] is that of a woman [playing around with another woman] the action is regarded as mere obscenity.”

We pasken like this Gamarra, as set forth by the Rambam in Hilchot Issurei Bi’ah 21:8, stating “For women to play around with one another is forbidden and belongs to ‘the practices of the Egyptians’ concerning which we have been warned, ‘You shall not copy the practices of the land of Egypt’…But though such conduct is forbidden, it is not punishable by lashing since there is no specific prohibition against it and in any case no sexual intercourse takes place at all. Consequently, such women are not forbidden to the priesthood on account of unchastity, nor is a woman prohibited to her husband because of it, since this does not constitute unchastity. But it is appropriate to flog such women since they have done a forbidden thing. A man should be particularly strict with his wife in this matter, and should prevent women known to indulge in such practices from visiting her, and her from going to visit them.”

As such, a woman in this position would not be considered a sotah and would be permitted to remain with her husband even if he were the Kohain Gadol

The Babylonian Talmud sets forth in Yemavot p.76 A that relations between women are not considered actual sexual relations, stating, "“And even according to Rav Eleazar, who stated that an unmarried man who cohabited with an unmarried woman with no matrimonial intention renders her therefore a prostitute [zona], this disqualification ensues only in the case of a man, but when [the case] is that of a woman [playing around with another woman] the action is regarded as mere obscenity.”

We pasken like this Gamarra, as set forth by the Rambam in Hilchot Issurei Bi’ah 21:8, stating “For women to play around with one another is forbidden and belongs to ‘the practices of the Egyptians’ concerning which we have been warned, ‘You shall not copy the practices of the land of Egypt’…But though such conduct is forbidden, it is not punishable by lashing since there is no specific prohibition against it and in any case no sexual intercourse takes place at all. Consequently, such women are not forbidden to the priesthood on account of unchastity, nor is a woman prohibited to her husband because of it, since this does not constitute unchastity. But it is appropriate to flog such women since they have done a forbidden thing. A man should be particularly strict with his wife in this matter, and should prevent women known to indulge in such practices from visiting her, and her from going to visit them.”

As such, a woman in this position would not be considered a sotah and would be permitted to remain with her husband even if he were a Kohain.