Among the year's most surprising high-profile splits were those of lovey-dovey-looking red-carpet fixtures Katie Holmes and Tom Cruise, Heidi Klum and Seal, Amy Poehler and Will Arnett, and Jennie Garth and Peter Facinelli.
"Twilight" film franchise co-star Facinelli filed for divorce from "Beverly Hills, 90210" alum Garth in March after 11 years of marriage, citing "irreconcilable differences" as the cause for the split. The couple have three daughters -- Luca, 14, Lola, 9, and Fiona, 5.
Fashion model and TV personality Klum filed for divorce against Seal, her recording star husband of six years, in April, stating they had "grown apart." The parents of four children -- Leni, 7, Henry, 6, Johan, 5, and Lou, 2 -- were known for their public displays of affection and lavish vow renewals on each wedding anniversary.
Although former "Dawson's Creek" cutie Holmes and "Jack Reacher" hero Cruise were targets of breakup rumors almost immediately after Cruise announced their relationship while jumping on Oprah Winfrey's couch, the couple always spoke glowingly of each other in interviews and appeared happy in public.
However, Holmes filed for divorce in June after five years of marriage. She now lives in New York with her and Cruise's 6-year-old daughter, Suri. Neither side has publicly offered an explanation for the breakup, but speculation is Cruise's close association with the Church of Scientology drove a wedge between him and his third wife.
Comic couple Poehler and Arnett are keeping mum on why they decided to break up shortly after marking their ninth wedding anniversary in August. The "Up All Night" actor and "Parks and Recreation" funny lady have two preschool-age sons together.
Kristen Stewart and Robert Pattinson, who play star-crossed lovers in the "Twilight" movies, temporarily broke up this summer after four years of dating when Stewart admitted having a brief fling with Rupert Sanders, her married 41-year-old "Snow White and the Huntsman" director, in July. She and Pattinson reconciled later in the summer and are reportedly living together now.
Calling it quits for good this year were "Vegas" actor Dennis Quaid and his wife Kimberly, Broadway icon Ben Vereen and wife Nancy; "Survivor: Philippines" contestant and ex-"Facts of Life" star Lisa Whelchel and husband Steve Cauble, singer Stevie Wonder and wife Kai Millard Morris, "The Big Bang Theory" cast member Mayim Bialik and husband Michael Stone, and musician Kenny G and wife Lyndie Benson-Gorelick.
Headed to divorce court as well were "New Girl" actress Zooey Deschanel and rocker husband Ben Gibbard, comedian Martin Lawrence and wife Shamicka, and singer Sinead O'Connor and husband Barry Herridge.
Making happier headlines by getting married were "Magic Mike" star Matthew McConaughey and model Camila Alves, "Black Swan" Oscar winner Natalie Portman and dancer Benjamin Millepied, "Hitchcock" actress Jessica Biel and pop singer Justin Timberlake, "Gossip Girl" lead Blake Lively and "Green Lantern" hero Ryan Reynolds, and comedian David Cross and "Sisterhood of the Traveling Pants" actress Amber Tamblyn.
Also swapping vows in 2012 were reality TV personality Jack Osbourne and Lisa Stelly, singer Annie Lennox and Mitch Besser, "The Hangover" star Zach Galifianakis and Quinn Lundberg, actress Tichina Arnold and Rico Hines, "The Devil Wears Prada" scene-stealer Stanley Tucci and Felicity Blunt, musicians Wynonna Judd and Cactus Moser, and R&B idol Bobby Brown and Alicia Etheredge.
Perhaps the most closely watched engagements of the year are those of film stars Brad Pitt and Angelina Jolie -- who have been together for seven years and have six children -- and Pitt's ex-wife, actress Jennifer Aniston and actor-screenwriter Justin Theroux, who confirmed their betrothal after about a year of dating. Neither couple has announced when their respective weddings are to take place.
Hopping on the celebrity baby bandwagon this year were birth-giving actresses Reese Witherspoon, Jennifer Garner, Megan Fox, Drew Barrymore, Sarah Michelle Gellar, Alyson Hannigan and Hilary Duff. Reality TV personality Tori Spelling gave birth in 2012 to her fourth child.
Singer Nick Lachey's current wife, Vanessa, and ex-spouse, Jessica Simpson, also both had babies this year. Simpson is wrapping up 2012 pregnant with her second child by her beau, former football player Eric Johnson.
Of all the adorable celebrity offspring born this year, the one who seemingly grabbed the most headlines was Blue Ivy Carter, born Jan. 7.
Thanks to media reports of the high-security, luxury suite in which she was born in a Manhattan hospital, as well as the cute snaps her famous parents posted online, the first child of rap mogul Jay-Z and Grammy Award-winning singer Beyonce is already a wee starlet in her own right.