Deceipt - Phase II

Through the years Rob and I had a ups and downs like any couple.
We didnt argue much but actions spoke louder than words.
In the late 90's an aunt of mine was suffering from terminal cancer. One of my dearest aunts. I remember as a child she lived with us for a while, I always held her close to my heart, so seeing her suffer as she did was very disturbing to me.
I at this point had moved into another apt over a shop, something Ive always wanted to do for some strange reason.
One night I came home, Rob was on the sofa. I had recently acquired a PC.
I went to check my emails as I normally did. I, for whatever reason checked my "sent" folder. I never did this but again for some reason, without suspicions I must add, I looked into my sent. I never thought that Rob was using my pc, not that he couldnt at that time, its just that that thought never crossed my mind...UNTIL!!!
In my sent folder, as Rob sat on the sofa, I found an email that Rob ahd sent to this guy named "Christiano" - I read the email in which Rob was telling Christiano, how he was a romantic, fun, usually home by 11 and to call him. There was more than one email and I recall one email saying that Rob had waited for his call, but Christiano hadnt called.
I had just returned from a visit with my mom who was torn at my aunts situation, so I was a bit blah. Finding that emailchanged my mood instantly.
I called Rob over to my desk and asked him to look at the computer screen. He went white and quiet. He denied the email. I told him to get out of my house. His reaction to that was to grab my legs and cry, No!! in a sad upset tone. I was done, I said, "get out!" and he did.
Now this wasnt the second time I caught him,more like 3rd if not 4th time I found him trying to get with other guys. I still didnt get it. If he wanted to be with other guys, if he wanted to go back to his "slag" days then I told him to let me go!
Again days passed and we got together again. What is/was my problem?
He couldnt possibly have loved me enough. They were just words.He was on automatic when it came to telling me he loved me.
I remember telling Rob I loved him long before we even became a couple.
For the first few months Rob never told me he loved me.
One day, when I had gotten let go from a job I had, I was upset.
Rob came to pick me and take me home as he was in school and not attending that day.
On the drive home, and only after seeing me being a blubbering mess, he uttered the words he loved me. He told me he loved me when I was upset, to ease my feelings of being let go? That too should have been a sign but again I was in love.