[robertpaulsen]

From another article:

"He (Pedersen - rp) said he had contact only with Dina Matos McGreevey during the trysts, and wasn't sure whether McGreevey was gay."

So Mr. McGreevey watched. Maybe that's technically a threesome, but that's not what I would call "engaged in a threesome".

[Lucius Cornelius Sulla]

So Mr. McGreevey watched.

Or he and the other guy BOTH had contact with Mrs. McGreevey.