This is one of the biggest fallacies in resume writing, but I hear it all the time. No, your resume does not need to be limited to just one page. That doesn't mean it can't be one page - it just means it doesn't have to be.
Not to pick on them, but I think it all starts with career advisors in schools and colleges. I am sure they recommend one-page resumes (as they should, since people starting out on their career most likely only need one page), but they probably don't explain that the "need" to stick to one page diminishes once you have a longer work history and more to brag about. Or, equally possible, the students forget. Unfortunately, the end result is many people who are well into their careers still think they have to limit their resume to one page.
I see it all the time - people with 6 different jobs in the last 15 years squishing it all into one maxed-put page with thin margins, incredibly small fonts, and no white space to separate anything.
It makes for an awful reading experience and it severely hampers their job search.
Yes, it's true there are some people out there who believe everyone's resume should be one page. But according to all the polls I've seen and all the networking I've done, they make up a very small percentage of resume readers. Most people are perfectly fine with two pages, and there are even some that are okay with three.
Since an important part of resume writing is minimizing risk of rejection, here is my "golden rule" for resume length:
I have written thousands of resumes since 2005 and I can say this - only one was three pages, maybe 5% of them were one page, and the rest were two pages.
I encourage you - don't limit yourself to one page if you need more room to tell your story.
All the best!