sex life

i need help! my boyfriend and i have been dating for about 3 months, talking for about 5-6 and we’ve had sex probably about 10 times, but lately he hasn’t been able to finish. it could probably be because he was a virgin before me and sex is still kind of new and we have only like 3 positions💀. guys what can i do to fix this we haven’t been able to finish the past few times we’ve tried! is it me?!