I've been getting shit from him for 15 years. I found out I was pregnant just after he went off with another woman. He accused me of sleeping with his friend 
, at 6 months he told me to have an abortion, he came back when I was 7 months for a few weeks, then went off with her again when I went into premature labour. He didn't tell me, one of my friends saw them together in a nightclub.
After ds was born the broke up and he used to wake ds and I up at 3am every few days so that he could sleep on the floor (pissed). I went back to work when ds was 3 weeks old (I didn't know it was illegal) and he borrowed my entire wages so that he could go to Germany with his friend and (promised to give it back when he came home but he never did. I had to leave work so it was all the money I had).
He lived with us for a few days when ds was a few months old as he'd offered to look after ds whilst I found a job but went out with his friend for 'a pint' and didn't come back for 2 weeks. He'd often never turn up to see ds, he never paid maintenance (but did once the CSA made an assessment when ds was 2). I moved so he couldn't crash on my floor when ds was 1 and things improved a little, contact was regular and he stopped using my home as a hotel as it was too far for him to walk.
He stopped seeing ds for a while so I took ds to see him, as he was asking about his dad, and he threw us out of his house (ds was 3). He did apologise and sat in my living room in tears. A year later he left the UK, then didn't see ds for 3 years. Contact was minimal (one letter in 10 years, a handful of calls and emails), and he'd turn up without notice and demand we dropped everything so that ds could see him. He was always hungover, always intimidating and never listened. If I said we had plans he'd shout down the phone at me and accuse me of keeping ds away from him . This carried on until a few years ago when he shouted and swore in ds's face (ds was 11) during a visit. Ds decided not to see him (thank fuck) so he decided to stop paying maintenance. I took him to court and I'm still going through this to get the arrears (they couldn't award all of it as they can only backdate to when you file the forms. They did almost double it though as he's always refused to increase it and has a better paid job. He also refused to pay it into my bank account, so it went into ds's. Not good if you're trying to shield a child from the fact that their parent isn't paying maintenance for them). The ex got married about 6 years ago, they have 2 children. He didn't tell ds that he was going to have another sibling, and he sends ds no photos/cards/anything from them. He didn't contact ds at all for 6 months because ds pointed out a grammatical error in an email. I had to ask ds to apologise in the hope that his father would start paying maintenance again (his mother said that this was what he wanted), but he didn't.
He ignores my emails and texts, and sends ds birthday cards with 'see you soon' written in them (nothing for Christmas for the past couple of years). He won't put my surname on the envelope (ds has my surname). He's lied to his family about me, blaming me for ds not seeing him (it's all down to me, apparently). Ds hates him and thinks he's a looser and I couldn't hide the lack of maintenance from him as it used to go into his bank account. When his father can be bothered to email, ds replies and that's it. Then he'll get another a year after. Ds goes through phases where he doesn't feel secure and wanted, can't imagine why! 
I'm hoping he does just piss off and leave us to it. As I said, 15 years of shit. If you have one like this, then you're better off running.