I've heard the same thing, but I didn't know how true it was. So
I found a post on /r/AskHistorians laying out the historical evidence:
We have no conclusive proof that gladiators were used as prostitutes by Rome's wealthy women. In fact, I can go a step further and say that Rome's men most CERTAINLY did not like the idea of such a relationship - however, that's not to say that it didn't happen. There's a really good part of *Emperors and Gladiators* that almost specifically concerns this question - I'll type it out here for you.
> Women as well as men found gladiatorial contests, and gladiators, attractive. Some much-quoted epigraphic evidence suggests that this attraction might be sexual: at Pompeii, the *retarius* Crescens was known as 'the netter of girls by night' and 'the girls' darling'. Thracians were a favourite symbol of manliness because much of their body was left visible to the audience. This obviously constituted a potential danger to the Roman male's control over his womenfolk. Augustus restricted women, other than the six Vestal Virgins, to watching gladiators from the rearmost rows of seats. It proved impossible to put a stop to stories about sexual associations between gladiators and women of the elite, even including empresses. The wife of Marcus Aurelius, Faustina, was suspected of having had affairs with gladiators; only this could explain why her son Commodus was so interested in the sport. ... Roman anxieties about the sexual attractions of gladiators are given expression by the fact that they are classified together with prostitutes in Roman legislation, and that grammatical texts associate the Latin word for the gladiator's trainer (*lanista*) with that for a pimp (*leno*). Like pimps and prostitutes, public performers such as actors and gladiators sold their bodies for the delectation of others, if only visually.
Again - sorry about the long quote, but I believe that it matches your question perfectly; while we have nothing in the way of SUBSTANTIAL proof that they were used as prostitutes as Hollywood suggests, we do have proof that the men of Rome were threatened by them. They were considered prostitutes, doing the equivalent of selling their bodies for the pleasure of viewers, and rumours abounded about their possible sexual conquests.
Roman rumour was a pretty big deal to them - it was a large part of how the latest news got spread, and it really defined Romans. So when rumours (especially about the Empress!) had these women sleeping with gladiators, it was a comment on their character. Whether those rumours were spread by political opponents or the people is tough to say - however, the propaganda wars of Rome are *legendary* to say the least.
To add a little to his post, there were certainly Roman women who would have been rich and/or daring enough to carry through on their gladiator fantasies. So while it doesn't sound like it was as open as gladiators being formally rented out to wealthy women for sex, there probably was at least a little sex happening.
(Edited 10 minutes later.)
@previous (Killer Lettuce🌹 !HonkUK.BIE)
This is ahistoricism. It's a well known fact everyone in Rome was a flaming homo. All they did was make buildings, mint coins, and engage in passionate homosexual exploits.
@previous (C)
If you want some Gay Rome, I can post about that too. Here is some gay graffiti.
@previous (Killer Lettuce🌹 !HonkUK.BIE)
Roman pineapples. Fact or
non-fiction?