I am reading, "Same Sex Unions in Pre-Modern Europe," by John Boswell. I think he's making a fairly convincing case of it, and (for me) is doing so in part by making it clear that many of these linguistic interpretations can be ambiguous, and he acknowledges that repeatedly. He lays out his entire case for the paired saints in question being homosexuals, and I think he does a pretty good job of introducing reasonable doubt.
However, when I mentioned to a history professor of mine a year or so ago that I was interested in the book, she was extremely dismissive and said Boswell was too invested in his own work and had lost all objectivity. I'm aware Boswell was gay, but I don't think that precludes the validity of his scholarship, and it seems solid ... however, I only dabble, and the professor in question is an expert in American marriage and family history. What's the overall opinion of historians who study Greek, Roman, early Christianity, and pre-modern Europe? Boswell reliable or no?
Just to clarify, Boswell is actually a medievalist by trade. While linking to Wikipedia is not exactly welcomed in this sub, I think we can make an exception for references to the bibliographies of historians: https://en.wikipedia.org/wiki/John_Boswell.
If you look at his writings, you will see that all of his works are about homosexuality in medieval Europe. While I cannot vouch for his treatment of the entire sweep of premodernity, he is certainly grounded in the methodologies of a medievalist. I cannot vouch for that book, but I certainly wouldn't dismiss him. A number of his graduate students went on to become current leaders in the field of medieval gender/sexuality studies.