<human>: Can you condense the text into three sentences or less?

I have started seriously dating a guy I have liked for a long time and am thrilled that we are finally together, but I am extremely insecure about one of my best friend's relationship with him.

The two of them are casual friends but because I interact with both of them regularly, I am constantly confronted with how much the two of them are alike. They like all the same music, movies and TV shows and have similar worldviews and temperaments. My boyfriend and I are alike in some ways, but not all of those. I end up comparing myself to her all the time these days and freaking out about him eventually discovering how much they have in common.

What's worse is that I can't avoid spending time with the two of them together forever because we live in the same university town and have a lot of mutual friends. Plus he likes spending time with her and I can tell that he has a good time with her.

Is this an insecurity issue? How much do commonalities matter in a relationship anyway?
<bot>: I feel like my boyfriend and one of my good friends have more in common than the two of us do and I am constantly comparing myself to her and falling short.