Not that I'm defending Mormon ideology, I'm not, I think it's screwed up too, but I think you are being unfair.
MOST of the prophets in the bible are insanely screwed up. King David had hundreds of wives and concubines, and had people he didn't like murdered, including a husband of a woman he wanted to sleep with. I know David wasn't a prophet, but he was 'A man after God's own heart' and was held up as an example in many ways.
So I don't think it's fair, even if you don't agree with the person's choice of religion, to simply say that 'their religion holds up this person I don't like, therefore I can't support them', that mirrior can be turned around too easily.
You almost got it right. David had his way with Bathsheba, got her pregnant, tried to fool her husband, Uriah, but was unsuccessful. Since Plan A didn't work, he sent Uriah into the heat of battle and had this general retreat and leave Uriah fighting by himself. See: 2 Samuel 11:2-17:
"2 And it came to pass in an eveningtide, that David arose from off his bed, and walked upon the roof of the king's house: and from the roof he saw a woman washing herself; and the woman was very beautiful to look upon.
"3 And David sent and enquired after the woman. And one said, Is not this Bathsheba, the daughter of Eliam, the wife of Uriah the Hittite?
"4 And David sent messengers, and took her; and she came in unto him, and he lay with her; for she was purified from her uncleanness: and she returned unto her house.
"5 And the woman conceived, and sent and told David, and said, I am with child.
"6 And David sent to Joab, saying, Send me Uriah the Hittite. And Joab sent Uriah to David.
"7 And when Uriah was come unto him, David demanded of him how Joab did, and how the people did, and how the war prospered.
"8 And David said to Uriah, Go down to thy house, and wash thy feet. And Uriah departed out of the king's house, and there followed him a mess of meat from the king.
"9 But Uriah slept at the door of the king's house with all the servants of his lord, and went not down to his house.
"10 And when they had told David, saying, Uriah went not down unto his house, David said unto Uriah, Camest thou not from thy journey? why then didst thou not go down unto thine house?
"11 And Uriah said unto David, The ark, and Israel, and Judah, abide in tents; and my lord Joab, and the servants of my lord, are encamped in the open fields; shall I then go into mine house, to eat and to drink, and to lie with my wife? as thou livest, and as thy soul liveth, I will not do this thing.
"12 And David said to Uriah, Tarry here to day also, and to morrow I will let thee depart. So Uriah abode in Jerusalem that day, and the morrow.
"13 And when David had called him, he did eat and drink before him; and he made him drunk: and at even he went out to lie on his bed with the servants of his lord, but went not down to his house.
"14 And it came to pass in the morning, that David wrote a letter to Joab, and sent it by the hand of Uriah.
"15 And he wrote in the letter, saying, Set ye Uriah in the forefront of the hottest battle, and retire ye from him, that he may be smitten, and die.
"16 And it came to pass, when Joab observed the city, that he assigned Uriah unto a place where he knew that valiant men were.
"17 And the men of the city went out, and fought with Joab: and there fell some of the people of the servants of David; and Uriah the Hittite died also."