stepparent adoption law in washington. Washington

[CR1985]

i am in Washington state as well, i have a 2 year old daughter that after my fiance and i get married he would like to adopt and i had a one night stand with a man after a long night at the bar and i don't remember his name or even where he is now.. so what would i have to do to go through the adoption process.. my fiance is air force and my daughter is on state medical and i don't want her to lose her medical insurance and not be able to be put on his medical. i was wondering if anyone could help me out on this