Princess123,

What you are talking about is love being a feeling.  Feelings are transitory as anita has pointed out.  Mature love is a more than those goo-goo eye feelings.  Google the difference between mature vs. immature love.

Mature love is based on mutual respect, trust, and acceptance of each other.

Your boyfriend’s “mistake” was to snoop through your emails.  This was not respect or trust.

Do not get hung up on why you are “falling out of love.”  Examine why you “need” to stay with this person.  Do you love and respect yourself?  Would you advise a close friend to tolerate such behavior?

You gave examples of current and past boyfriends and their behavior.  Note the pattern for those relationships and work on yourself so you will be able to have a healthy, trusting relationship next time.

Mark