Soft during sex

my boyfriend and I had sex yesterday and during the second round he became soft. I didn’t think much of it because we already had sex and we both drank a little. but tonight we were barely 10 seconds in and he became soft. it bothered me a little, but then he left the room and came back only to not say a word to me but also to put headphones in and watch tv on his phone. what should i do?