1 of 6
After filming the 1992 comedy Love Potion No. 9, Sandra Bullock began dating her costar, Tate Donovan. The couple even got engaged – but split after three years. "The person who needed me most was always the person I was attracted to," Bullock tells PEOPLE of the split. "My priorities were him first, me second."
2 of 6
Were they or weren't they? Bullock was linked to the Dallas Cowboys quarterback in 1995 – but the ever-private movie star never confirmed their romance.
3 of 6
"He's become a powerful force in my life," Bullock says about McConaughey, her costar in 1996's A Time to Kill. In true Bullock form, the twosome insist they're just friends – even though McConaughey did tell InStyle, "I just look at her and I think, 'Wow!'"
4 of 6
Four years after moving to Austin, Texas, Bullock begins dating the local indie-rock singer. Keeping a low profile, she often supports him at his gigs, and his track "Bullets" was featured on the Miss Congeniality soundtrack in 2000. "As celebrities go, Bob and I have a very low-key relationship," she said. "We live our life together one day at a time."
5 of 6
Age, schmage! While filming the 2002 thriller Murder by Numbers, Bullock begins quietly dating costar Ryan Gosling – who is 16 years her junior. The twosome keep the romance under wraps, and date for more than a year.
6 of 6
He was supposed to be the love of her life. After marrying the Monster Garage tycoon in '03, Bullock treats James's three kids as if they were her own. "I have children, amazing children," she gushed to PEOPLE. But now amid his cheating scandal, Bullock has filed for divorce and is facing single parenthood with a new baby, Louis.
Peta Murgatroyd and Maks Chmerkovskiy Share Sexy Anniversary Tributes
FULL EPISODE | People Now Tuesday December 6, 2016
35 Celebs Who've Stood Up to Unrealistic Body Standards
WATCH: Milo Ventimiglia Continues to do Push-Ups — This Time with Ellen DeGeneres on His Back
Game of Thrones' Peter Vaughan Dies at 93