Living Together Before Marriage There are two more letters on this topic, and also a Q+A titled "What's it like to be married after living together?" that you can navigate to from the link above.
Living together before marriage often has the opposite effect that couples intend when they decide to cohabitate: it weakens the later marital relationship. For this reason, it is not a good idea, despite any other circumstances you might be experiencing. Living together for the next 8 months doesn't get your marriage off to the start it deserves. Especially with a baby on the way, you need all the encouragement and support you can get, including your in-laws'.
From a religious perspective, I don't believe it's the "living together" that is a sin, it's sharing a bed before marriage that is sinful. To the extent that living with your baby's father would tempt you to continue a sexual relationship with him before marriage, you will struggle to stay on the path God intends for your relationship. God is loving, God is forgiving, but still He wants us to turn from what we know is sinful - regardless of whether it's for a short time or a lifetime.
To weigh practical considerations (like being together with the baby's father in your new family's home, and having someone else to help care for a newborn) with your religious and in-law considerations, is it possible to be married sooner? Having just gotten married myself I know what a tremendous amount of work a wedding can be, but a lovely wedding can be put together in a short time period as well. I think that would be the most ideal outcome for you!
Good luck, and let us know how you're doing, whatever you decide.
