A source close to Mel and Robyn Gibson — who this week announced they were divorcing after 28 years of marriage — alleges that the atmosphere in the couple’s home was often a giveaway that things were not right between the couple, people.com reports.

“The tension between Mel and Robyn was obvious. Even during family dinners, they wouldn’t speak sometimes. Robyn would pretend that everything was perfect. No one would ever dare to ask her how she and Mel were doing,” the source tells People.

The problems seemed to become evident three years ago, the magazine alleges. “During the summer of 2005 the whole family had a great time hanging out at the Gibson’s Malibu beach house, but at the beginning of (2006), Mel started having severe depression and went back to drinking massive amounts of alcohol. It was all very stressful for his wife,” says the source.

“At the same time, Mel was under tremendous pressure while filming Apocalypto in Mexico. The movie got delayed because of terrible rainstorms... Mel’s drinking got out of control because it was very difficult for him to deal with the pressure of producing the movie,” people.com quotes the source as saying. In papers filed this week, the date of the couple’s marital separation is listed as Aug. 26, 2006 — less than a month after Mel Gibson’s profanity-laced DUI arrest.