Since this took place prior to the 1850 Census when all people in a household are identified, you'll have to use old historical documents that aren't online. The Missouri State Archives have microfilm of Platte County's probate records and wills 1840-1893. They have circuit court Records 1839-1856. and county court records 1839-1856 and index to marriages 1839-1894.
Another source for microfilm is the Mid Continent Public Library. Your local library can arrange inter-library loan of these microfilmed records. Successful Searching!