Sister's need

My sister's car was a heap of rubbish, rarely worked for very long. Always failing at the worst moment. But she had no choice but to carry on, as they say, unable to afford any replacement herself. We both lived in the city, well away from our parents. At 34, I was successful career-wise, somewhat lacking relationship-wise. My sister (31) was in and out of relationships, career wasn't going at all well. Then a chance arose that would greatly improve her career. But to secure it, she would need a reliable car, as the job involved travelling around the city daily, and buses wouldn't help as too slow and didn't serve all areas needed. We lived separately; I had no car, didn't need one for my job. Also, I lived close to my workplace, and my sister lived miles away from hers. I was actually closer to my sister's workplace by several miles than she was. Also, I had a spare room she could use. But she preferred her own place, so she could bring her boyfriends back. With me there, it would be a turn-off. But not in a current relationship and needing a car asap. Desperate enough to offer herself to me to get a reliable car. She offered to offer herself to me for a year for regular sex. In return, I would get her a reliable car, not a new car, just a reliable one. I agreed, mainly because I could retire my hand and stop using hookers. She, of course, moved in with me straight into my bedroom. She fulfilled her end of the bargain from the very first night. I got her a secondhand car, a well-maintained one. I had a friend check over first, and it would be very reliable, he said. She got the job on a trial, and if she showed she could handle it, it would be hers full-time. She planned to stay the year with me and then find her own place again. I was really enjoying the sex after a somewhat awkward start. Then, in the ninth month of our agreement (Christmas), we partied a bit too much. She got pregnant after just one rubber broke. She has reactions to the contraceptive pill, and so doesn't use them. Anyway, at first we weren't worried, till the signs of pregnancy started to show up. But not people to even think of an abortion, unless there was something very wrong with the baby. It was fairly easy to pass it off as planned, pretending to be married. My work colleagues had little knowledge of my personal life. Her colleagues just accepted that she had married and would still use her maiden name for work. Being pregnant hasn't hindered her job in any way, and my workplace provides childcare. So, when the baby arrives, we have everything covered.