What this girl wants? Marriage — and a prenup! A source says Christina Aguilera is finally ready to marry her fiancé of nearly a decade, Matthew Rutler, provided he signs on the dotted line.

“Her lawyers have started working on it, and Matt says he’s willing to sign whatever she wants,” the insider exclusively tells In Touch. “She’s promised that she’ll make sure he’s not left high and dry if things don’t work out.”

Christina, 43, who shares a 9-year-old daughter with Matt (her 15-year-old son Max’s dad is first husband Jordan Bratman), may be waiting to make things official until Valentine’s Day — the 10th anniversary of the engagement — and has already scheduled a break at that time from her Las Vegas residency.

“Christina knows how much Matt wants to get married,” adds the source. “They’re looking at doing a destination wedding.”

Have a tip? Send it to us! Email In Touch at contact@intouchweekly.com.