footloose and fancy-free

be footloose (and fancy-free) (without responsibilities or commitments; able to do anything one desires in one’s life without any restrictions) — совершенно свободный от обязательств; без обременительных обязательств; сам себе хозяин (часто о несемейных); ~ свободен, как вольная пташка;
свободен, как птица; свободен, как ветер

Example 1: "Have you got a girlfriend?"
"Not at the moment. I'm footloose and fancy free!"

Example 2: Bill, six years older than Sally, was ready to have kids, and lots of them. Sally, still feeling footloose and fancy-free, was thinking maybe two at the most, but later.

Example 3: Well, I think Dodi was 42. He was footloose and fancy free. I'm not saying he didn't have girlfriends because he was an attractive man.

Example 4: "Footloose and fancy-free," was how he described himself to her, but Rosalind didn't buy it. (Michelle Cliff, Transactions)

Example 5: “You could arrange things so you could take a honeymoon without selling out,” Bass said. “I hate to lose you as a partner, Harvey.”
“No, I wouldn’t leave a business behind in which I had all my money tied up,” Pemberton said. “I’d worry about it so I’d be a rotten companion. I want to step out footloose and fancy-free.”
(E.S. Gardner)

Example 6: ...Earlier, she sat at the kitchen table in her bathrobe and drank two vodka tonics, which she'd never liked before and still doesn't. She feels as if she's rooting around for some trapdoor into the life she's supposed to be living now: single, footloose and fancy-free, that sort of thing. (Becky Hagenston, Holding the Fort)

Related vocabulary:
free as the wind

(as) free as a bird (completely free to do what you want and without any worries; at liberty, without obligations)

Example 1: Can you join us tonight? Yes, I'm free as a bird. (dictionary.reference.com)

Example 2: She'd been travelling alone round the Greek islands for a year - free as a bird. (thefreedictionary.com)

Example 3: He's free as a bird he can travel wherever he chooses. (dictionary.reference.com)

(as)free as the air
Example: No, I'm not married. I don't even have a girlfriend. I'm free as the air. (thefreedictionary.com)

[one's own person]