Things between Bill Belichick and his 23-year-old girlfriend definitely appear to be serious ... as TMZ Sports has learned the couple has been living together for months.
Sources close to the duo tell us ... Jordon Hudson moved in with 72-year-old Belichick at the ex-New England head coach's home in Hingham, Mass. right around the start of the new year -- and since then, where one goes, the other isn't far behind.
