my husband chatting with women

Assalamu Alaykum brothers and sister.
I am an Arabic woman who got married a year and half ago with a reverted man,and has a kid from past relationship. However I thought be not a problem, and I decided to marry him anyway because noone is perfect.
So I met them online in a chat, and decided in a month to marry him, first time when I started to know him was a charming mand kind and respectfull, after marriage he changed compolitely his behaviour got worse with time he shaut and even insult me, and accused me of lying and manipulation.
I don't know what to do sometimes things goes worse.
One day we had an argument he said that I don't listen to him,and that I should obey him, and do what he saYs.
Whence most of the time I just try to express my opinion that probably is different from his point of view, sometime he follow me and acted like I am the crazy one and started shouting at me and tellinghullik me that he has enough when I am actually not doing anything... His behaviour is making me crazy.
Another day we had another argoment basically because of his sons behaviour. He asks his son to give me chips and he Throw on me the chips and laughed, and when me and my husband start arguing his son stand behind the door listening what we are saying.
I spoke to my husband about this and I was concerned that probably his son doesn't like me, and he said to me probabilyour I have done something something he doesn't like.
We went to imam and we spoke about everything and the imam advice us to me to obey my husband and to my husband to control his angeroom. Things didn'the improved
I tried to look forward and be more good to him and forgive him whatever he does to me but he look not wanting to forgive.
One day I was looking at his phone and I find that he was chatting with a Muslim lady who doesn't wear islamicaly the appropriate clothes.
I told him that I know about that and he said to me that he will get married againext and he doesn'the want give up his right.
When I met him first time we did speak about polygamy and he know my thought about it, I told him that I want to marry a man who doesn't accept polygamy and he said to me that he wasn't looking to marry again and he want just one wife. He did give me his words.
Now his telling me that he didn'the said that and that he want to get marry again and that I should write down on the marriage contract before the marriage that I don't allow him to have more than one wife... Is this mean his words before the marriage doesn't count anything? The premises he gave me don'the have any meaning?
Another thing we didn't register at the council, we only did nikah.
Today I see that he is chatting with women, when he did premes me that he will not.
At this point I am thinking of divorcing him. Please help me I don't know what to do, I am in pain and I can't sleep at night and I don'the know noone to ask for advice.
(Sorry for any grammar mistakes or spelling)
Jazakumullahu khayran