My boyfriend likes to slumber party

today I broke up with my boyfriend because he thinks it's ok to sleep at his friends house every week once or twice. This has been an ongoing issue in our relationship and we fight about it all the time. he don't think there is anything wrong and tells me that he's going to continue sleeping out if he feels like it. in my opinion a man always comes home. I don't understand why a grown man finds the need to have his slumber parties and no t care. today I packed his shit as he's sleeping out again. am I exaggerating or am I right to be upset