פירוש על קידושין 102:1

Rava responds that the end of the mishnah could be read as supporting him. A man says to a bunch of women, “Behold you are all betrothed to me.” The sisters are not betrothed, but the non-sisters are.
So what exactly did he say? If he said “all of you” then this would be like a case of a person who says to another person and a donkey (or any animal), “You and the donkey should acquire this.” Since the donkey cannot acquire, the other person does not either. So too here, since the sisters do not acquire the betrothal money, neither would the non-sisters.
Rather, he must have said, “one of you [is betrothed to me].” The sisters are not betrothed because this is “kiddushin that cannot be followed by intercourse” since he could not have sex with either one of them.
This discussion continues tomorrow.

Abaye here solves the entire mishnah such that according to both clauses, kiddushin that cannot be followed by intercourse are valid kiddushin.
Clause 1: If he betroths two women simultaneously that cannot be betrothed consecutively, neither are betrothed. This follows Rabbah’s rule.
Deduction, part 1: If he betroths only one of these women, both are doubtfully betrothed. The kiddushin are essentially valid even though they cannot be followed by intercourse.
Deduction, part 2: If he explicitly says that he is betrothing only the one who is allowed to have sex with him, neither is betrothed. Since he does not know which one he is betrothing, neither of them can have sex with him.
Clause 2: This is exactly what the husband said. The sisters are not married not because “kiddushin that cannot be followed by intercourse are not valid” but because he explicitly stated that he was betrothing only those eligible for intercourse. Thus Abaye has resolved this clause with his opinion.