The pair began dating in 2011 and have remained private, sparingly mentioning each other on social media.
The young actors are no longer together, said the 28-year-old Ushkowitz at "The Normal Heart" premiere in Beverly Hills on May 19, E! News reported.
A videographer is said to have asked her if she and Trevino were still together, but she replied, "No, we're not together anymore," as she was signing autographs.
However, the split seems to be amicable, with the actress saying that she and her ex-boyfriend are "wonderful."
No word yet on what caused the breakup.
Ushkowitz and Trevino, 29, first publicly debuted their relationship at the 2011
In January, the "Glee" songstress celebrated her beau's birthday on Instagram with a throwback photo of them at that awards show.
"Happy birthday to my best friend, the one who has taught me how to laugh and love more and more everyday," she captioned the snapshot.
Weeks later, she shared an image of Trevino's "Vampire Diaries" cast chair.
In November 2011 the pair joined actress Emma Roberts for a risque photo shoot and collaboration with photographer Tyler Shields in which Trevino and Ushkowitz posed for several seductive shots.