This happened to my dd. Her partner tried to strangle her and I noticed she was wearing a scarf round her neck in the summer and long sleeved tops to cover up her arms. She was very thin. She was being denied food and her bank card was taken, she had no access to money and when she went into the bank her account was emptied and overdrawn.
The Police arrested her partner twice. On the second occasion the officer attending remembered her from the first time and told her for god's sake get out before you are killed. They locked her partner in the cells but he returned. His friends had actually called the police as they were so scared.
He also smashed her head against the floor, punched her whilst they were out for not wearing suitable clothes, kicked her car full force in a rage and dragged her out of her home in the winter in her nightclothes and locked her out in the street in the freezing cold. He smashed up the lap top we bought her.
The police have this person on a list where they can warn future partners. Partner said he would deny violence but agreed to plead guilty to harassment for which he was convicted. My dd could not face court. But he served a prison sentence anyway because he did not bother attending community service.
What I am saying here is that this is just the beginning. You don't want to believe it because the thought of moving on by yourself and "throwing" away your long term relationship is so scary. I am really worried for you because I still think you are minimising the strangulation. That is the acknowledged end of the line in any domestic abuse situation.
You need to block contact for a while so you can get your head straight. His pressurising you is very worrying. You will not feel the same again. Don't spend the next few years walking on egg shells.
We thought her partner was decent, intelligent and good for her. How wrong were we.