Warning signs I should have heeded:
Saying "you will never meet anyone as good as me".
Looking in the mirror, grinning and saying to himself "you are having a good looking day". And telling me that he had always dressed well and "had an eye for colour" 
Calling his ex a "psycho bitch from hell" and me believing him. I can see now that he used the same mind tricks on her. She did sound vulnerable with family issues, but I can see now that he belittled her, ground her down and ruined her self confidence until she probably did suffer depression and a break down. Then he got scared when she got mentally ill and binned her, triumphantly confident that she was broken into bits by their relationship ending.
He kept all (and there were A LOT) his love letters from his ex. And not just in a box in the attic - they were everywhere; between the pages of books, hidden in a pen box, inside CD cases, in suitcases, etc etc. I can't work out if they used to hide love notes for each other to find and he left them there or if he put them there for him/me to stumble across. Prob both. I'm sure he used to enjoy coming across the notes himself - they were incredibly passionate and romantic (they met doing English Lit) and it delighted him and stroked his monstrous ego that someone loved him so much and he cast them aside. He also delighted in my finding them and teasing me for being "jealous" and "insecure" - then refused to gather them up or put them away in a box because they were "part of his life that he can't change" and I shouldn't be so nosy!!
"Banned me" from buying a pair of knee high boots because they would make me look like a "slut". I didnt realise he was quite serious, so laughed and bought them anyway - i wanted to wear them with opaque tights and a knee length wool skirt, so hardly slutty! He then threw a monstrous temper tantrum, including holding my wrists and bawling in my face said we were finished because I "refused to accept his opinion". If only I had accepted that we were finished!!
I had kidney stones which were quite debilitating, but didn't stop me trying to live my life and go to work - he loved to play the ministering angel and kept telling me not to do things because I wasn't up to it, was too frail, too delicate and that I needed his support. I see now that he liked that i was ill and tried to make me dependent on him. in hindsight, he was reading too much Bronte, ha ha!
Told me that he loved me because I was a size 8 and that I'd better not put on any weight, because he could never be attracted to someone big. Due to illness (see above) I weighed about 7 1/2 stone, but he encouraged me to cut out cheese and not snack between meals.
Being incredibly jealous of my job and repeatedly saying that he was just as talented and intelligent, if not more so, than me and he couldn't understand how i got that job and that he should have got it. This is notwithstanding that he got poor A Levels and got into university on clearing and failed several interviews for similar jobs.
Throwing an almighty temper tantrum in the pub in front of everyone, because a (mutual) male friend bought me a rose from one of those table rose sellers. This was not withstanding that the friend bought them for all the women in our group, that he was gay and we had all urged him to as a laugh because he was so flamboyant. According to ex, only he had the right to buy me flowers and I should have thrown it in the bin if I loved him.
I'm sure there are more....!