Could u stay friends who treated u like this?

This person doesnt sound like a person that you should be getting involved in, also if you knew he was engaged to be married you shouldnt have got involved in this, as its a bad situation to be in. I know it just happened but as you soon realised what was happening, it should have ended right there and then. He was leading you on, and you accepted that you was going to be 2nd best, but you shouldnt. If you do take him back, in years to come you will regret it. Personally i would be civil if you ever bump into eachother, but do not and i repeat do not get into a relatioship with this person because he'll treat you the same. Forget about this man and move on with your life, you deserve someone who respects you, and this man doesnt.