DATING someone who doesn't have the same passion

Brooke
I have been dating a guy for about 5 months now and things have been going great! We have had sex and hangout all the time. He's met my whole family, yet I have not met his. 
The other day he brought something up and said he thinks everything between us is "there" EXCEPT that I am not into his botany that he studies. 
I do my best to ask questions and I truly am interested in his studies! I have passions as well and I don't feel like he asks much about what I do. 
So what do I say to him? Why would he bring that up ? Is that shallow of him?