Please don't judge :(

Having a really difficult and upsetting time I've been with my partner for 5 years but on and off a lot! We have a lil boy together however we are very unstable always arguing etc there has been violence on his part before we don't live together and it's basically at an end. However I slept with someone on a night out (yes I no I am very stupid) and am now pregnant I'm almost 100% sure it's the one night stand. I don't really believe in abortion but am considering it, I have wanted another baby for a long time but do I wait to have another with someone in my future who I no will be around to help or continue with this pregnancy although it'll cause a lot of drama and abuse. I no it's my fault I'm not looking for sympathy just really need people's advice as I'm really stuck and depressed on what to do :(