kinda freaked out?

my boyfriend of 1 1/2 years has been telling me that he thinks he has signs of an STI, and asks me if i've cheated on him. i most DEFINITELY have NOT. never would i ever cheat on him. he has asked me this before but it was about a week ago when he said it burned when he peed. now he's texting me again asking if i've cheated. i haven't. i'm about to have a panic attack bc i don't want him thinking i have.

i really need opinions and comfort right now..