1a.  Indiana Works Progress Administration.  1940.  Index to Marriage Records, Sullivan County, 1850-1920 Inclusive, Volume III, Letters O-Z Inclusive.  Online at GenealogyLibrary.com.  On p. 203:

Trimble Charles	July Ann Willis	Sept 19 1851	Book 1	p.  94
Trimble Charles	Susannah Cox	Dec  18 1856	Book 1	p. 434

1b.  Marriage Index:  Indiana, 1851-1900 (Broderbund CD-243):

Trimble, Charles	Willis, Julia Ann	18 Sep 1851	Sullivan Co.
Trimble, Charles	Cox, Susannah	17 Dec 1856	Sullivan Co.

2.  Census Records:  Indiana, 1860 (Broderbund CD-304):  Carlisle P.O., Haddon Twp., Sullivan Co., p. 740, 239/299:

Charles Trimble	36	M	W	Farmer	800	600	Indiana
Susan Trimble	25	F	W				Indiana
William Trimble	14	M	W				Indiana
Nancy Trimble	12	F	W				Indiana
John Trimble	8	M	W				Indiana
Joseph Trimble	3	M	W				Indiana
Benj. F. Trimble	1	M	W				Indiana

The older children are Susan's from her first marriage.

3.  1870 Census Images (online at Ancestry.com; Image #52 of 57):  Merom P.O., Hadden Twp., Sullivan Co., IN, p. 118B, PN 52, enumerated 28 Jul 1870 (extracted by Diana Gale Matthiesen):

1870:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	9	10	15	19
390	347	Trimble Charles	47	M	W	Farmer	3200	1145	Indiana		/
		_______ Susann	36	F	W	Keeping house			"
		Cox William C	24	M	W	Farm hand			"
		___ Nancy M/W	22	F	W	At home			"
		___ John	18	M	W	Farm hand			"	/
		Trimble Joseph	12	M	W				"	/
		_______ Benjamin	10	M	W				"	/
		_______ Rush	9	M	W				"	/
		_______ Catharine	4	F	W				"	/
		_______ Edward	3	M	W				"

Listed next to Harrison ALLSMAN, one one side; and, on the other side, listed three households from Edward & Permelia (SHAKE) WILLIS. 

4.  From the History of Greene and Sullivan Counties, State of Indiana... (Goodspeed, 1884: 760):

CHARLES G. TRIMBLE, farmer, P.O. Carlisle, was born where he now lives, Haddon Township, Sullivan County, Ind., November 26, 1823, one of nine children born to Joseph and Catharine (Carico) Trimble, both of whom were natives of Kentucky, who came to Sullivan at an early day, and where they died, she dying January 3, 1871, and he January 12, 1873.  The education of our subject was such as could be obtained from the old subscription schools, and he was reared to farming.  September 22, 1851, he was married to Julia Willis, who bore one child, which died in infancy, April 22, 1854, the mother following her loved one in eight months thereafter.  December 18, 1856, he was married to Mrs. Susannah (Cox) Cox, by whom he has had five children -- Joseph, September 18, 1857; Benj. F., March 14,1859; Rush, March 2, 1861; Catharine E., September 5,1863; Charles E., September 17, 1866; all living but Benjamin, who died August 22, 1877.  The farm of Mr. Trimble consists of 320 acres of well-improved land, upon which he raises, in addition to the usual crops, considerable stock.  Subject and wife are members of the Christian Church at Bethany, he having been a member since 1851, and she since 1842.  He was formerly a member of the Patrons of Husbandry, being one of the charter members; is a Republican, and takes an active interest in all matters pertaining to his party or the public.  He also looks with satisfaction upon the fact that he was never before a grand jury nor sat as a petit juror.