So, earlier this year, the actor sought therapy.
Gibson, the pal says, "wanted to figure out how to extricate himself from this unhealthy relationship peacefully and calmly. Which is what he did."
Indeed, the couple's split around March appeared smooth on the surface, and in May the two signed a custody settlement for their 8-month-old daughter, Lucia.
Gibson's lawyer Stephen Kolodny previously described the deal as "very generous support payments, joint custody and eventually 50/50 custody of Lucia," while the Russian singer claimed that payments have since dried up.
But over the last few weeks, things have imploded in a very public way, with Gibson, 54, and Grigorieva, 40, locked in a bitter custody dispute and the superstar facing domestic abuse allegations and the fallout from leaked audiotapes in which Gibson berates and threatens Grigorieva during profane rants.
A source close to the case claims the tapes were recorded in February on the heels of a heated exchange in January.
Both sides agree they argued in January but differ on what exactly transpired. Grigorieva claims Gibson punched her in the face "more than once," breaking a tooth and knocking out a veneer. Another Gibson source says the actor only "tried to stop [Oskana] from shaking their baby like a ragdoll" during the altercation.
And how Gibson is holding up amidst both the public and private drama? The actor is still in therapy and, says the friend: "He's coping as well as can be expected."
For more on the Mel Gibson story, pick up this week's issue of PEOPLE, on newsstands Friday