should i demand a marriage to the father of my kids? we have 5 yr old son and 1 yr old daughter. we're living together since i got pregnant for my first child. but we never had a chance to talk about getting married. and i dont what to ask him too. because i dont want him to think that im forcing him. i want him to initiate on that.

I think there is no harm to bring it up since I assume there will not be any major change to your current arrangement. Perhaps he just didn't see a need or thought you wanted to go through the paper works. I, too, think that it will be better for your children since they will likely be asking questions (or asked by their peers). Still, it is a decision between you and your partner. At the end of the day, it is your commitment to each other that really matters. Getting married legally is just so you have papers to show for. Do whichever that works best for you. Have a chat with him. :)