So I posted a month ago about STBXH threatening to get "custody" of our two DC. This is all because I am in a new relationship, of which I have introduced the DC to very carefully and they are very happy about.
Following his threats, I consulted a solicitor so confirmed that, although it is his right to apply, under the circumstances (he does not contribute financially, he lives with his parents where there is no room for two DC to live, he does not currently work) his claim would have no substance. I pay for everything including expensive after school child care in order that we could both work.
The divorce will be finalised in a couple of weeks. His application included our agreement that the DC reside with me, but I work damn hard at ensuring he gets a lot of quality time with them. He sees them during the week after school until I get home, when I collect them and take them home to bed. Then most weekends I have one day with DC where he doesn't see them, then the other day he will spend a few hours with them. On occasions I have said they would like sleepovers, it's dependant on his social life and hobby 
So Saturday night, 11pm, I had a phone call to say Ex had been out, paralytic drunk, and bumped into new man's father, where ex tried to get in a fight with him. Then followed 2 hours of phone calls to me from ex screaming abuse, making threats if violence to new man, and again threatening to "go for custody". I apparently used to take drugs 20 years ago and that is enough for me to lose DC to him
I have never taken drugs in my life!
I have been advised (solicitor also told me this) that I should register a complaint to police against him, but I am scared of making the situation worse, but then I can't even leave the house now without looking over my shoulder and feel I am being watched.
I have been completely honest with DC about ex's behaviour over last few weeks, and as much as they love him and enjoy sleepovers etc, they do not want to live with him.
So what do I do? I pay for everything and just scrape through the end of the month, I have no savings, I rent our house. I can't afford to pay high solicitors costs. My friend said I should sit tight and wait for his solicitor to write to me, then see a solicitor, cos it could just be him blowing hot and cold, but I can't live like this, he is making me ill but ultimately the only people he will hurt are the DC and that breaks my heart 