Oh Lou this just gets worse and worse for you 
Again..... mine done the same, he had her pregnant within a week of meeting her. I took him back, once againshe was pregnant the week after he was here for 1 night (I knew that night it would never work, I had lived alone with boys for a year and it was nice without him there).
With me it took several visits to infertility clinic, taking my temp every morning, then a laparoscapy (sp too late to google) told my tubes were fecked, given a IVF price list but then strangely I had no period after this op, and was pregnant.
I love my DC dearly they are my life, without them I would be nothing, I was really a "single parent" even when he lived with us, he was never hear, did nothing with them, never attempted to save for Christmases or birthdays he relied on my parents and me paying into an account weekly.
I detest the fact he is their father but can and will deal with that. My boys give me the strength and love to do so.
I too think he may be lying, he sounds the type to do so sadly, if he is not or even if he is please consider having no contact with him. do it via solicitors if affordable, don't take his crap and horrid comments, he is abusing you and not even with you. I wish I knew his address 
Reading back throughthe posts I am now terrified I am going to received a huge bill from my solicitor!!! I will check that out tomorrow.
Take care of yourself, big un-mumsnets hugs, you must feel awful, I know that feeling and it's just heart-renching. 
Things will get better, it will take time, but you WILL move on from this horrid place you are in right now.
Please take care of yourself.