Pregnant - BF doesn't want it, what should I do?

My BF & I have only been dating about 4 months. I was on mini pill but missed one and have now found out I'm pregnant. OOPS. We're both in our early 30s, I have a child already so I know just how hard/easy that is on my own. I was planning on having a baby on my own in 1-2 years time before I met him.
BF's life is COMPLICATED at present. Big issue is that prior to meeting me his ex had been cheating on him with multiple other guys and fell pregnant, she has no idea who the biological father is & she's not due for a couple months yet so no resolution of that for a while. She has done so much to destroy his trust and has been very demanding of him. He's afraid.
He's a sweetheart and is trying to be supportive of me but it's just too much for him and he wants me to abort. I'm pro-choice and not religious at all, but I don't feel that aborting would be right for me right now. I'm not prepared to announce just to get some outside opinions, so I'm turning to you, what would you do?