You may go back to the computer now.
Both parties in a romantic partnership need to have the experience of being listened to and acknowledged. One of the most effective ways to achieve this is to encourage the other person to pursue their passions and aspirations in life while providing support for them to do so.
It is revolting to think that your boyfriend, of all people, would try to “mansplain” anything to you. If your boyfriend doesn’t have your back, how can you expect anyone else to do so?