Unless he is busting the pop charts, as talented as he may be, in truth, he is an aspiring musician. Actors and artists sometimes struggle with finding their place because they are often, as you (and he!) said, very good at what they do and want to share it with the world. Unless they’ve kept their talents in the realm of a hobby and have a substantial day job, they may have faced ridicule or judgment from family members about their career path as a musician. He may need to posture and be seen due to feelings of inadequacy.
Remember, whenever someone needs to fluff their feathers, the unmet need is like one of attention, affection, approval, or appreciation (the 4 a’s). This behavior pattern can be addressed in therapy; he would have to want to do that.
Ask yourself: Is this person kind at his core? How does he treat people outside the realm of intelligence? Is he bragging and putting you and others down because he feels unseen or otherwise misunderstood? How ingrained is this way? How often does it show? How does it show up?
You can kick him to the curb, for sure. Or, you can take pause and say to him, “Hey, I have something I’d like to talk with you about that may feel a bit uncomfortable at first but that I’m hoping can ultimately bring us closer together.” If a partner won’t willingly dive into important conversations, it doesn’t bode well for the future. If they will, and they are fundamentally a kind person with core values that align with yours, then you may have yourself a keeper.
No one knows the answers to these questions but you—and you do know the answers! So, be radically honest with yourself and then make a decision so you don’t waste years of your life with someone who is not willing to look within and make changes for their own improvement and a deeper connection in the relationship. If he is willing to talk about it and get outside help, overcoming this dynamic can become a superglue toward a lifelong bond.