Not to bring up a sensitive subject, but Amy Poehler and Will Arnett have broken up*. I know, I know. It makes me extremely, horribly sad.
While moping about this recently I started thinking: what could have soured in their relationship? I started to imagine what it must have been like to be married to someone who does the same thing you do---in Amy and Will's case, they're both actors, and comedians. There's a lot of community and support in a relationship like that, but there must also be some degree of competitiveness.
Then I thought, what if I was in a long-term relationship with a fellow novelist? And that novelist also wrote contemporary fiction? How could I read their work without thinking, "How would I have written this scene?" At least for me, that would be downright impossible. I know because I've been a critique partner/beta reader for friends who also write contemporary fiction, and I have that thought all the time.
If you're feeling a similar sense of competitiveness cloud your judgment while beta reading, or in accepting notes from others, I recommend seeking out friends who write in genres outside of your own.
It can be intimidating to think of critiquing genres you don't know entirely well. But really, that outsider perspective is what makes you such a valuable asset. When I beta read a high fantasy book, I don't think at all about how I would write it since I've never done it. That lets me relax and truly be a reader, taking the story at face value and giving notes that are much more useful. Likewise, in my last round of receiving critique, one of the best set of notes I got was from someone who writes action-packed thrillers. She saw things others didn't, and her feedback was tremendously helpful.
I'm not suggesting that you only get feedback from critique partners of different genres---just don't be hesitant to ask for their help, or to dive in and critique something different yourself. Sometimes it's true that opposites attract.
Though I'd give anything for Will and Amy to reunite.
*This is old news, technically, but the pain hasn't abated.