Much more overt than when?
Certainly in Caligula's time it was far more overt and not hidden than even today.
There were some critical differences, though. It's hard to tell how common it really was. We can't judge by the antics of the extremely wealthy and powerful--stuff the emperor did was no more common in that society than the stuff we see on the covers of celebrity magazines are common in society today. It gets recorded and reaches historical record
because it's uncommon.
In the 1st century, homosexuality may have been common, however the idea of homosexual marriage definitely and provably was not.
Particularly, the concept of "dominant" and "passive" were a firm fixture of their homosexual practice. Roman soldiers, for instance, were permitted to practice homosexuality as the dominant partner, but not as the passive partner. A Roman soldier found to have been "passive" in a homosexual coupling would be executed.
There is a famous recounting, for instance, of a young Roman officer (probably still a teenager) who was strongly pursued by a Roman senior officer. The younger man resisted and finally stabbed the senior officer to death. In an ordinary case, this would have resulted in the conviction and execution of the younger officer, but in this case, the other officers were aware of the situation, so the younger officer was absolved of guilt.
The same kind of attitude was prevalent in civilian life as well--a man known to take the "passive" role was not considered a full male citizen and was shut out of functions such as holding office. It was a crime for an older male to have sexual intercourse with a freeborn male youth because that would cut him off from the citizenship priviledges of being a freeborn male.
This doesn't mean that such a man would not gain social celebrity and even wealth--but it would similar to the status of the owner of a popular brothel in more modern times.
Marriages in Roman society were for the purposes of building legacies, status, and political and economic power. Therefore, a homosexual marriage would not be considered, except as a farcical dallience of someone who already had all the power (such as an emperor) and even then it had to be kept discreet...even emperors wound up dead if they went too far.