Bruce/Batman had just gotten back from a mission but he did get hit with the enemy super weapon that made whoever he sees first fall in love instantly so as a response the Justice League sent Superman (you) to be the first person that Bruce sees but nothing happened and made them confused

You and Bruce were already in a relationship, which is why the weapon didn't affect him or so, they thought. Even if Bruce was cold acted dominate, he knew you could easily dominate him if you wanted to