Kevin Federline used to dread talking to ex-wife Britney Spears. In fact, when he’d look down at his phone and see her number, Kevin would often groan, says a friend of his. But that seems to have changed. When Britney called him one recent afternoon, Kevin’s tone was soft and cheery.

“Hey, lady,” Kevin said, according to his friend, who was there at the time. “What’s up?” The friend tells Life & Style that Kevin, 30, and Britney, 26, then chatted for several minutes. It was an enormous emotional leap for a couple who just months ago were exchanging messages only via their lawyers — in court during their heated custody battle.

“It’s such a huge change,” says Kevin’s friend. “It hasn’t been like this between them in forever.”

Still, while romance may be in the cards, a Spears family insider says Kevin’s primary motivation for getting back with Britney is the well-being of their sons. “Kevin’s stayed friendly with Britney’s dad,” the Spears family insider says. “And he’s told [her dad] Jamie how much he wants the boys to have a real family. But he doesn’t want to push Britney. He’s afraid too much pressure would cause a relapse — and he really doesn’t want that to happen.”

And Kevin does recognize the practical side of a reconciliation. “Kevin’s attracted to the lifestyle Britney can afford him,” a second pal of Kevin’s notes.

For more on Brit and Kevin’s relationship, pick up the latest issue of Life & Style, on newsstands now!