Sounds like bi erasure to me, they were happily married to their wives and had relationships with men

Nerva was never married, and Hadrian was distinctly not happily married.

Trajan was married, but is often considered to have been in a ‘lavender marriage’, so to speak, despite getting along well with his wife.

Hadrian and Trajan could be considered to be bisexual depending on how you read the sources, but are generally considered to be homosexual, or so close to it that the modern label is broadly applicable.

There are a large number of bisexual Emperors in Roman history - Augustus, Tiberius, Caligula, Nero, Titus, Domitian… that there are a handful that can probably be considered homosexual by modern standards is in no way erasing bisexual representation.

Also did these “great” emperors own slaves? 👀

Yes, as was the norm of the time.