Emotionally & physically abused in past relationship

I was in an emotionally and physically abusive relationship for 10 years at first it was what I thought perfect he could do no wrong then little by little the names started the cheating started I forgive him everytime it really crushed my self esteem and self worth I found myself trying so hard to just do everything that little bit better that the last I thought maybe I was the problem it wasn't good enough then the odd slap here and there and the discusting verbal abuse really got to me to the point I felt worthless I started to self harm forward to the last year he headbutted me I knew I had to get out and I did! I never spoke to anyone family or friends about what was happening it's been 1 year since yes I've had calls texts one minute they are nice next back to the same old abusive person I've finally managed to start a new relationship its early still it's been 4 months he is the sweetest guy ever he compliments me always is always there when I need him he makes me feel wanted safe and like I'm the only girl in his world but I'm finding it hard to stop pulling back and let my guards down I'm scared its going to happen again he knows about my previous relationship he understands fully and is always trying to reassure me but it's so difficult I know I will end up pushing him away and I really don't want to any advice please on how to cope with these thoughts and feelings