Sofia Vergara and Joe Manganiello were "always very different".
The 51-year-old actress and Manganiello, 46, tried to make their romance work, but they've always been distinctly different characters.
A source told PEOPLE: "Sofia is down to earth and fun to be around when she is stress-free, but as a career woman, she also cares what people think about her, and revels in what makes her a major star."
Manganiello, on the other hand, has been described as being a "guy’s guy".
The celebrity duo recently split after eight years of marriage, with the insider admitting that there were "several things that didn't work" for them.
The source explained: "Their physical attraction to each other only carried their marriage that far.
"On a day-to-day basis, there are so many other things that need to work. There were several things that didn't work."
Despite this, Vergara and Manganiello made every effort to make their romance work.
The insider shared: "They were really trying to make it work though.
"They do love each other. No one wants to constantly bicker with their spouse though. Joe has absolutely nothing bad to say about her. She is a great woman. They were just not great together in the long run."
Vergara and Manganiello recently announced their split, describing their break-up as being a "difficult decision".
The duo also claimed that they still "love and care" for each other.
They said in a statement: "We have made the difficult decision to divorce.
"As two people that love and care for one another very much, we politely ask for respect of our privacy at this time as we navigate this new phase of our lives."