Husband Cheating

I have anxiety, so I'm probably just feeling that. But I'm worried my husband is cheating on me. 
My dad cheated on my mom and my step mom. I was cheated on by my first boyfriend. My aunts husband cheated. I've been surrounded by cheating my entire life, so I think it's just become a fear of mine and by default I worry about it in my own marriage. 
He says he would never cheat and there is no one else for him, but sometimes I see him hiding his phone a bit or turning it away from me. And I've started noticing him liking this one girls pictures on Facebook more and more, which I know could be nothing just liking a picture, but today she announced she's separating from her husband... 
So not to seem paranoid or over protective with my husband, but my anxiety has been triggered hard and I just need to hear someone's option on it. 
And if he is, I don't understand what it is that makes me... Not good enough.