Can we afford to keep our baby?

We've just found out I'm pregnant, about 5 weeks but head is telling me one thing and heart another. 
My Partner and I have had multiple discussions, every time he says financially he doesn't think we can do this. We have sat down and worked out all of our finances and there's no question that it's going to be a hell of a struggle. Im also not entitled to statutory maternity pay as I won't have worked 26 weeks on my 15th week before I'm due. We would therefore have to claim maternity allowance and see what other help we could get. 
I have a loan and a car on lease which also doesn't help matters. 
I really want to keep our baby but I don't want it to be brought into a world where we are continuously struggling. My Partner says he thinks it will put a massive strain on our relationship, and he's probably right. The last thing I want is to lose him, I couldn't do it without him. 
I'm also worried about after the standard maternity leave ends, how we would manage then. We don't have any family or friends close to us who could help. 
I'm trying everything possible to find a way that on paper we can do this, so that I don't have to go through the heartbreak of a termination. 
Does anyone have any advise? Or have been through this? I don't know what to do for the best. My head says one thing and my heart another. I desperately want our happy family but if we can't financially manage it's going to be anything but happy.