Is it normal for guys to have bicurious thoughts?

I've been married for over 10 years and I have caught my husband emailing guys several of times saying how he's bicurious but he won't ever admit anything to me. the only answer I have ever got from him about why he would email guys is because he just wanted attention and compliments which I think is bs but I would've never expected this from him so is normal for straight guys to be bicurious?
Is it normal for guys to have bicurious thoughts?
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