Hi all, I just wanted to update this thread. Thank you for the support you offered when I was in a state. I honestly never imagined he would do such a thing. When I posted it initially, the app messed up and subsequent posts came up under my normal username, which is the main reason I had to stop updating the thread. Now that I have ended the relationship, I don’t mind it being linked.
To answer a couple of the questions, I had no access to money that night because my salary has been entirely spent by that point in the month and I have no savings. I think I wrote that to deflect suggestions about going to a B&B or something (I wasn't thinking straight). I didn't call the police that night because the DC were sleeping and I didn't want them to be woken and find out what had happened.
So it took me a couple of weeks but at the end of May I called the Police and they took him away. He was drunk again and my son witnessed his appalling drunk behaviour. Thankfully the other DC (DSD and DNephew) were not in the house at the time. He's been gone for 2 and a half weeks and I'm doing ok. I have had the police and social services on my phone quite a lot, and had a home visit too. When they released him it was with conditions not to contact me for 28 days, which I'm making the most of. I'm speaking to my landlord about changing the tenancy into my name (he is reluctant because we were accepted based on our joint earnings, even though I've assured him I can manage the rent alone).
At the moment he is staying with my Dad, and my family are facilitating contact between him and the DC. I've agreed with DSD's mum to continue having DSD come to my house and be with us on weekends and she will see him with DS during the weekend but come back to her room in my home at nights.
I've been clear with him that it’s over. I don't want to be with him anymore. This was the first time his abuse had ever had a sexual element, but there's been plenty of verbal abuse over the years as well as many, many outbursts resulting in broken furniture (the last one is what DS witnessed the day he was arrested). Apparently he has been sober since he left (only got my DBro and DSis word for this and they can't always tell when he's been drinking so am taking this with a pinch of salt) and has been to the doctors for help with his alcohol problem. I assume he's doing this with a view to getting back together some time in the future so I will need to stay strong to keep him from talking his way back in. I sound stronger than I feel.
What happened that night changed how I felt. Many times before he has got drunk and smashed things and by the next day I was willing to forgive and 'work through it' (yes I know how misguided this was). This time, he had done this awful thing to me and all the love I felt for him that had kept me trying had gone. That made it almost easy to call the police and get him out when the next drunken outburst came.
I know I shouldn’t have waited, but after that night I spent the next two weeks in a dazed funk. I just couldn’t think straight, I just felt so broken because I've allowed my boundaries to be pushed SO far that he actually thought I would forgive that and could carry on as normal. He even tried it on with me, rubbing himself on me, making me feel sick! When DS saw him smash the furniture, I snapped out of the funk and finally felt some clarity. That is the first time any of the children have actually witnessed him smash something. He's done it before but always when they were out of the house, and we would always have an explanation ready for when they got home. All these years I've covered for him! But DS saw this, and I can’t have him growing up thinking this is ok. He was shocked and told DP off (he's 3 
).
I’m going to try and be strong. I’m not intending to let him come back ever, but people keep telling me “never say never”. To be fair to them, they don’t know that this happened, only about the violent rages and verbal abuse, which he is saying he will change.
This post has gotten really long so I’ll stop there. Thanks again all.