As they blissfully prepare to share their lives together in a new home, Ryan Reynolds and Blake Lively's whirlwind eight-month romance has hit a major snag. The couple's recent visit to his hometown of Vancouver erupted into a showdown between the Gossip Girl starlet and the actor's beloved mother, Tammy — causing a furious Blake, 24, to storm off, a source tells Star.

"Tammy would like to see Ryan with a woman who's not in the movie business because she feels that, ultimately, actresses put their careers first," says the source. "And she thinks Blake is pressuring Ryan into settling down before he's ready. He also rushed into his first marriage, with Scarlett Johansson."

Indeed, Green Lantern costars Blake and Ryan, 35, are "unofficially engaged" and planning to wed in the summer of 2013 at the $2.6 million estate they recently purchased in sleepy Bedford, N.Y., the source reveals. But Tammy is urging them to relocate to Vancouver full-time. "She says when they have kids, Blake and Ryan should raise them in Canada because it's safer," says the source. "Blake refuses to even consider that, saying that she has to be in New York for work."