help!

i lost my virginity to my current boyfriend, things started amazing, i fell in love quick, and best of all he made me forget all the things that my dad has put me through. Things have been really different lately he doesn’t wanna talk on the phone, he cancels plans, and he’s been hanging out with his ex late night i told him how i felt and he claims nothing has changed and told me i was crazy i don’t know how i feel anymore i kind of want to be single but he took my virginity and he made me very happy a while ago... what do i do?