Single parent and actually took the very real risk. I was 37 and desperate for a second baby. I had done it all the 'right' way first time, married, then two years later had DD, but he did not want any more and ended up leaving me for the OW after 10 years of marriage.
I admit I cried for a few weeks but then it dawned on me I could have another much longed for baby after all.
A year after ExH left I met a man in AOL chat rooms, not something I was trying to do, I just went there for company once DD was in bed.
We slept together on our first meeting. I was totally reckless honest about my lack of contraception and did indeed fall pregnant that first time.
DD is going to be 10 soon and we also have a DS who is going to be 9 soon. He moved 150 miles to be with me as soon as he found a local job.
I genuinely did not care about being a single parent at that point but when DD was born she was very ill and DP was amazing. I think I properly fell in love with him then!
So, yes, single parent over no child but it worked out I could have both.