Boyfriend troubles help:( need advice!?

Okay well i lost my virginity to him last saturday and we met on thursday, and then we had an argument because he has a new girl at his school shes from wales and he said shes a slag. but then i was with him at a place with other people and the suddenly he wants to invite her down and she didnt come down and we went his, and then he was texting her, she said shes coming down there in abit, and he goes hes at home and i goes say your with ur gf, and he was like -.- but did, and hes putting 3 'xxx's at the end of each text, then he wanted me to go home at 6, and then his mate rang him, and my boyfriend said that all his mates went to there house, and my boyfriend she hes going to the mates house there was no girls there, but then he argued with me about something else, which was depressing i felt like iw as gonna cry, we made up in the end. but then today i found out by some girl that he went down to the place we was at and met that girl there and then walked her home? so he lied to me? wat should i do:(? i was crying when i heard because hes known to be a player until he got in a relationship with me.