You have a boyfriend you think is possessive? Are you sure? What if it turns out that what your boyfriend did was because he really loves you? Don't let you decide on him for possessive reasons, but in the end you lose someone who really loves you. Recognize the signs. This is the difference between a real affection and a possessive attitude.
He asked to be sure, not to judge
If your boyfriend is possessive he will immediately judge, such as: "You were with A last night huh?!" or "Who did you go with?! (in a tinge of stoning)" A girlfriend who loves you will be different in how you ask. For example, "What time did you come home last night? Where did it end? If you go home, who's going to do it?" He made sure that you were safe. Don't assume that a question like this cornered you. It's you who should introspect yourself.