No it is not true that you necessarily need to be married. They will however look a little harder at your application and want to know how many years you have lived together and then they may require your partner to sign a financial guarantee for you. Also you will need to prove that you have swiss health insurance.

Once you have jumped through all the hoops you will likely be issued with a permit that allows you to reside in CH for 2 years (category B, sans lucrative activity). If you marry or get a full time job in CH you can apply for it to be changed to a 5 year working permit. 

As a EU citizen (ressortisant communautaire as they call it) you have  right to obtain a permit. They can give you a "permis de sejour" which can range from 3 months to two years. Be aware, however, that the procedure of getting a permit can take an incredible amount of time, depending on the commune you're applying in. High immigration communes such as Geneva and Lausanne are so busy that it isn't unusual for a permit to be delivered 6 months to a year after they receive a demand.

You will also need to prove that you can afford living here, be it by having a resident or a citizen sign a guarantee for you (that basically states they are willing to assume your living costs, medical expenses etc.) or by showing them a bank account in your name padded with a comfortable amount of cash. What Jenifer said about the health insurance applies as well. You should have one right now if you live in Switzerland. The fine for not having one is substantial, so if you plan on sticking around, get one.

As far as I can tell, there is nothing you can use in obtaining a permit that results from your relationship with your boyfriend. There is a possibility for certain permit holders to file for what they call "regroupement familial", but that is limited to spouses, minor children and direct ascendants who depend on that person. If I were you, I would just apply directly in your name, for your own account, provided that you can get a financial guarantee or have the means to live in Swtitzerland without working.

I'm sorry if I'm not being more precise, but a lot depends on your personal circumstances. I speak from my own experience with the immigration services, plus the limited theoretical knowledge I got from studying immigration laws at school. Don't be discouraged, though; what you want is doable and with a little help, I am sure you can get your permit.