AceShowbiz - Sylvester Stallone and Jennifer Flavin haven't completely resolved "their differences." Even though they are back together following a reconciliation in September, an insider has claimed that it is "not all bliss" between the 76-year-old actor and former model Jennifer, 54, - who had been married for 25 years when she filed for divorce earlier this year.

"They have a better channel of communication now but it's not all bliss. They have their differences, but in a long-term marriage like theirs, ending it and dividing up their assets would be difficult," the source said.

The "Rocky" star has daughters Sophia, 26, Sistine, 24, and 20-year-old Scarlett with Jennifer as well as sons Seargeoh, 43, and the late Sage - who died at the age of 36 from heart disease back in 2012 - with ex-wife Sasha Czack, and the source went on to explain that the pair's dedication to their family played a "big part" in their decision to remain together.

The source told PEOPLE, "They are both family-oriented. That had a lot to do with their efforts to stay together. For people in the public eye, they share an even more special bond in many ways. It really is often them against the world. It's a life few can appreciate."

The comments come just days after it was claimed that the couple were able to "work out their differences" and are "extremely happy." A representative for Sylvester said in a statement, "They decided to meet back up at home, where they talked and were able to work out their differences. They are both extremely happy."

Days before the announcement, a court filing lodged at a court in Palm Beach, Florida, revealed the couple had agreed "it is in the best interests of each of them individually, and more importantly collectively as a family, to resolve all issues attendant to the dissolution of their marriage in a dignified, amicable and private manner out-of-court."