The question asked is "Can someone else claim you as a dependent?"
Since you don't live with your parents more than half the year, the "qualifying child" dependent category is a No. That leaves "qualifying relative." A person can claim you as a qualifying relative dependent if they provide more than half your financial support. If the person is not a blood relative, you also have to live with them the entire year.
For support, you need to determine your total financial needs for 2020, that includes rent, food, utilities, transportation, medical care, tuition, entertainment, and clothing. If you live in your boyfriend's home rent free, then your need includes half the housing expenses (food, rent, utilities).
Then, determine how much you provided for yourself. Support you provide yourself includes money you earn or spend from your savings for your support, and it includes student loans in your name. Scholarships are not counted as either support or need, they are not added on either side of the equation.
Support provided by your boyfriend includes half the value of your housing (rent, food, utilities, etc.) plus any other costs he pays for you, like clothing or transportation. Your parents might provide some support if they cover you on their medical insurance.
If your boyfriend pays more that half the overall total, then he can claim you, otherwise he can't. There is a worksheet here that may help.
https://www.irs.gov/pub/irs-pdf/p501.pdf
