If I start dating someone before my divorce is final, can it be used against me (in a fault State)?
Dating before divorce can occasionally be used against you, especially if you have children. Whether you're in a 'Fault' State or not, you're best off keeping a low profile and postponing any serious dating until you're formally divorced.
This is as much out of concern for the children as anything else. Your children are almost undoubtedly going to have a difficult time adjusting to the divorce (more difficult than you will), and it's best to minimize the number of changes they will be forced to deal with.
If there's no paperwork specifying custody, can I keep my child in New York (for example) and not return him/her to Maryland (for example) while I file for custody?
You can, but this tactic may backfire on you. Judges don't usually appreciate this kind of interstate 'sleight-of-hand' with a child. The judge will likely see this for what it is: an under-handed trick to gain an unfair advantage in a custody dispute.
These kinds of maneuvers often worked ten or twenty years ago, but these days they're more likely to be held against you.
If the child has an established custodial environment in one State (i.e. has been living there for some extended period of time), your not returning the child to their residence in that State will probably be viewed as interfering in the child's normal life.
My girlfriend and I have a child together. I am listed as the father on the birth certificate. Could I take child with me if we broke up?
Technically you might be able to, but we'd caution you against simply taking off with the child.
You may be better off filing for custody before doing anything else, but as a parent you have every right to care for the child and provide the child with a home, wherever that may be.
If there is no custody determination or divorce decree, you can spend time with your child and travel with the child as necessary or as you see fit. If your significant other cannot provide a proper home, this would be all the more reason for you to care for the child at your residence.
SPARC message boards and see what advice you get. The users see this kind of thing all the time and can give you some good ideas and advice.
DON'T move out! This is the SINGLE BIGGEST MISTAKE people make. You could very well be required to pay the rent and the bills (plus a whole lot more) if you move out. Before you do anything, read these:
Again, DON'T move out. It's quite possibly the single biggest mistake you could make at this point.
See this article, Locating a ''Missing'' Ex-Spouse.