I have had to call the police only once (so I don't know if this is how it always goes but its how it was for me) and it was this year.
Called the police after my ex hit me during and arguement. I had 11 month old ds with me at the time.
He was arrested and taken for an interview under caution.
I was interviewed by the police and had to answer some questions on a questionaire sheet too (such as, has he ever mistreated an animal, am I scared of his reactions to situations, am I confortable leaving him to take care of the children etc)
He was bailed but as part of his conditions he wasn't allowed on my road (even though we lived together at the time) or to contact me.
I was given some information for domestic violence organisations (I called them but they didn't get in touch with me) and was also told that there would be a referral to social services as there had been a child in the house at the time.
Social services did turn up a couple of days later, they discussed with me what had happened and what I wanted to happen next. Looked around the house and made an appointment to come back in 2 weeks time to see how things were and speak to the children.
Had a visit from the local police just asking how I was, did I have enough support etc
They returned and asked how things were (I explained that the relationship was definitely over, and that I had seen a solicitor about residency of our child, severed joint bank accounts, removed his stuff from the house) they looked around the house again, spoke briefly to my older children (asked if they were happy, worried about anything etc). Left saying they were satisfied and happy with how things were going and would write to me.
Exes bail was up and he was told that the cps wouldn't be pressing charges. He was able to be on my road again etc (but had been scared by his experience so hasn't cause me any trouble)
Had a follow up call from the police after the bail conditions had expired, just checking everything was ok.
Had a letter 3 months later from social services saying we had been signed off and there would be no further action, and thanking me for my co-operation. Also inviting me to ask them for a copy of their report if I wanted to see it.
It sounds very scary but every person involved was nothing but supportive and kind to me. I can't fault the police or social services although I was terrified of their involvement.
There is support out there, but I found that you have to approach them rather than wait for them to approach you. I am sorry you've found yourself in this situation it's a lonely and scary place to be. I hope you are ok x