It’s been a long time since Natalie Portman was single — about 15 years to be exact — and she’s having a tough time. A source recently revealed how Portman has been handling her shocking split from ex-husband Benjamin Millepied, whom the actress finalized her divorce from earlier this month after nearly 12 years of marriage. “She’s struggling emotionally, so she’s enlisted the help of a top professional divorce coach to try to lift her spirits,” an insider spilled to a news publication around eight months after Portman quietly filed for divorce from Millepied amid rumors he was having an affai…