I have a very wonderful FP

She understands me and tries to help me 
She listens and wants to get into my hobbies instead of ignoring them or calling me childish

She sees the storm of my screwed up emotions and instead of running she holds my hand and walks forward

I've never had this kind of loving before, I've never felt so understood and wanted

I mean, she wants me in every aspect, she desires me and looks at me with the most loving eyes I've ever seen.

However

Sometimes I feel like some things she does/says are  because she's feeling guilty about doing something bad, a lot of times I catch myself thinking she's cheating on me even tho there's no clear proof of this

I mean, every morning she calls me before she gets to her work and afterwards, she texts me as soon as she wakes up and is always around texting/calling me

I've never had this kind of loving before or anyone who cares so deeply about me

But still the doubt lingers

Why if she's doing it because she feels guilty about cheating on me? 

I don't know if this is normal but it has seemed to be a constant in every relationship I've had, the doubt and the fear (it usually happens when I'm dating attractive girls) and the thoughts that they're somehow gonna end up hurting me

Is it normal? Does anyone's else feel this way? Am I just paranoid to that extreme?

Thank you