11/04/2008 at 03:15 PM EST
With her relationship
with Tony Romo approaching the one-year mark
, Jessica Simpson
is gaining some perspective on her life and loves.
"I'd always fall for guys I wanted to save," the singer, 28, tells Cosmopolitan
for its December issue (on sale Nov. 11). "For the first time, I fell in love with someone who saved me."
As for where the road with Romo, also 28, may take her, Simpson says, "I think any person who I'm gonna date for longer than six months, I definitely am investing in something long-term. If I get married again, then it will be the last time."
From 2002 to 2005, Simpson was married to Nick Lachey
, who, she says, "will always be a part of my life, but next time, I'm marrying the right one."
– Stephen M. Silverman RELATED GALLERY:
Jessica declares her love for Tony on the cover of PEOPLE