Ex on sex offenders register?

I'm 38 weeks pregnant with my ex's baby. I split up with him when I was 8 weeks pregnant because he was a control freak and treated me like complete sh*t!! I was left with depression and anxiety troubles up until I turned 25 weeks. My ex stalked me, harassed me. Even stalked my little sisters when they were being picked up from school. Just before I ended the relationship he turned round one night and told me that he had once been accused of rape and it was taken to court and now he is on the sex offenders register until the day he dies. (His words exactly) he is a drug addict and drinks alcohol like there's no tomorrow. He's told me in the past that he has a criminal record because he's aggressive and goes around beating people up.  I'm not putting him on the birth certificate because of all of this because I don't trust him one bit. What happens if he was telling the truth about the whole rape thing? I was raped when I was 13 so I'm worried about letting him near my baby. He reckons he's dragging me to court so he can get 50/50 rights. Can I be informed if he's on the sex offenders register? I'd bring it up in court but he'll probably deny saying it as it's my word against his! Can anyone advise me on this? I now have a loving partner whose willing to stick by me and my baby through thick and thin. I know it may sound harsh but I know for a fact my partner will be a better father figure than what the real father would be!! I'm from the UK..