A source told Radar Onlline: "For Will and Jada, holding it together these past few years has been tough because their marriage has been on life support for a long time."
It mentioned a confidiential US$240 million (NZ$366m) settlement.
"They're exhausted from trying to maintain the façade of a happy union ... They've decided to pull the plug in a carefully choreographed manner, [and] agree announcing their split at the end of the summer is the right move."
Magic Mike XXL actress Jada also addressed the issue in an interview with American Airlines' inflight magazine, saying she and her husband had become accustomed to the rumours, which have persisted over the years.
"Every year there's a new one," she told American Way. "And I'm like, 'Here we go. Get ready. Are ya holdin' on tight?'"
While denying they were heading for divorce, Pinkett Smith confessed their marriage wasn't always easy.
"Marriages go through shifts," she said. "And relationships go through shifts because in life, things shift. So people are automatically like, 'What's going on? They must be getting a divorce'," she said.
"Well, no. But when people feel those shifts and there's a mystery, they have to fill it with something."
In an earlier interview with Howard Stern, she praised her husband and said he was trustworthy and a "man of integrity" with "all the freedom in the world" - sparking rumours of an open marriage.
"When you can look in your man's eyes and know that he's holding you down and that he loves you, (that's) what's real. I'm not the kind of woman that believes a man is not going to be attracted to another woman."
While speaking to US Weekly in February, Will Smith also touched on the subjects of marriage and divorce.
"Jada and I have struggled with that a little bit," he told Us. "You'll realise that you're either really committed to having a relationship, or you're really committed to coming up.
"At some point one or the other is going to have to suffer."
- nzherald.co.nz
