"The truth is I did call my kids that evening," he writes on his Web site KelseyLive.com.
"Frankly, I was surprised that they did not call me in the morning but I was thousands of miles away and working that day so I didn't give it a second thought," says Grammer, 55, who is currently appearing on Broadway in La Cage Aux Folles, while Donatacci and their kids, Mason, 8, and Jude, 5, live in Los Angeles.
The Cheers star says that the couple had discussed flying the children to New York for Father's Day but decided to skip the trip since they were scheduled to come out the following week.
"I called them to see how they were doing as I do almost every night at around the same time, 11 p.m. my time, 8 p.m. their time, just before they go to bed," he writes. "Mason had been upset earlier that day because she was missing me. I spoke to her for some time and reassured her that I loved her and that I would be seeing her soon."
As for reports that he was spotted getting cozy with a blonde at a New York restaurant, Grammer clarifies that the woman in question was daughter Spencer, 26, from his first marriage.
"I do take issue with the characterization that we were smooching but surely if that were the case then even I admit it might be newsworthy in some fashion," he quips.
He adds that he will date again when the time is right. "Certainly, the time will come when I do see another woman," he says. "I expect Camille to see other men. I hope people and the press will understand that we are both free to carry on with our lives."
Addressing the reason for the split Grammer writes, "Camille and I had been discussing the possibility of a separation for some time before all this happened. She finally decided she should file. I respect her for this decision … I hope to have a great partnership with her in the raising of our children."
And as for future rumors, the actor asks fans not to believe everything they read. "Gossip and the rumor mill always thrive during times like these, as in the Father's Day story," he writes. "Whatever might be said, I ask that you take the 'high road.' I intend to do the same."