Congratulations on your pregnancy. By DV1, I assume you mean that you won the visa lottery, so double congratulations. You can enter the U.S. single and pregnant. Things become more complicated (but not impossible) if the child is born before you immigrate but if you immigrate and then the child is born here, there should not be a problem.
If you decide to marry the child's father, you should speak with an immigration attorney before you marry to discuss the various options you would have...
You can start the petitioning process from abroad. If your husband needs an affidavit of support, though, by the end of the petitioning process you will need to be domiciled or prove that you will be domiciled in the U.S. when he is ready to immigrate.
Whether your child automatically acquired U.S. citizenship at birth or needs to be petitioned along with your husband requires a more detailed analysis.
Very specific requirements have to be met before a U.S. citizen can lose her...
You will have multiple options for you if you divorce or separate from your husband, including if you entered into a good faith marriage and the marriage entered in divorce, you entered into a good faith marriage and he abused you, or your removal will result in extreme hardship. You may also be eligible for other forms of relief. It would be in your interest to speak with an experienced immigration attorney about these and other options.
Visa Waiver entrants give up important rights, including the right to contest removal other than through an asylum claim, so by failing to leave the U.S. when required you are risking a summary removal by Immigration and Customs Enforcement. With good counsel and some luck, you might be able to avoid this and obtain lawful permanent resident status without being removed or triggering a ban.
How likely it is that you will be approved for a visa and how quickly this could occur depends on an in depth analysis of your immigration case. It is dangerous to make generalizations about approval rates and processing times because each case is different and there are numerous factors that come in to play. If you want to put forth the best case possible in the best way possible, you should hire an experienced immigration law attorney.
There are multiple ways to follow up on a pending I-485 application, including Infopass, emailing the officer or supervisor, working with liaison, and, finally, filing a mandamus complaint in federal district court.
Don't rely on some random website. Immigration law is very complex. Decisions should not be made on an incomplete understanding of a partial statement of the facts. You need to have an experienced immigration law attorney review your case and help you navigate through the treacherous waters of immigration law.