As I've said before, the SWs have put themselves in a difficult spot here. If they wanted to give hope to abused women, they'd have given us a better storyline in the first place, with Helen seeking help to leave Rob and not assaulting him.
If on the other hand they wanted true realism, they'd have built this up over a much longer period and all the violence would have come from him, and perhaps she would never have left him finally.
As it is, they decided to go for sensationalism and high ratings with the stabbing and the trial. So in a sense they could now do anything, because they don't seem to be bothered about reflecting reality or giving hope to anyone in a similar position.
However, as Vango says, there have been hardly any prosecutions for coercive control and we all know getting a conviction for rape is not easy. It is to my mind entirely credible that Helen and Jess would decide not to go down that route. A rape trial would be absolutely vile. A CC trial might be marginally less traumatic, but again the defence would absolutely lay into Helen.
Far easier to get him into prison for a clear-cut case of assault if he finally loses his rag and does hit someone or get out his shotgun. And isn't that more like real life, too? Men who abuse their partners are far more likely to end up in prison for a physical assault than emotional or sexual abuse, aren't they?