Answer:
his loyalty to Portia
Explanation:
Brutus has a couple personal loyalties, one of which is his loyalty to Portia. This is because Brutus has a connection to Portia but that connection is still not strong enough for him to want to share his plans with her. Similar to his loyalty to Ceasar, although it was not strong enough for him to take part in the murder. All of these were personal loyalties.
