David had a wife. Her name was Michal. She was a princess, but King Saul gave her to another man while David was out and about running for his life. Here we read that David found another wife, although it doesn't seem that he was looking for one. Actually, David and his men were simply looking for some sustaining supplies, but the rich man (Nabal) was completely unsympathetic. Now, David had evidently been kind to Nabal's people and felt like Nabal owed him some kindness (I Samuel 25:15-16). So, being a man of war and feeling the offense of Nabal, David purposed to rise violently against him because of his evil attitude. But, God had other plans.
Nabal had a beautiful and intelligent wife named Abigail. Wisely she rose and corrected the error of her husband. In so doing she spared the lives of many from her household, and also prevented David from overstepping his bounds. In the process, she was taken from Nabal and given to David (Job 31:9-10 & II Samuel 12:8). God literally killed Nabal (because he was wickedly opposed to David... opposed to him for no good reason at all). David had intended to do it; to take Nabal's life from him (I Samuel 25:22), but God did it instead (I Samuel 25:38).
Now, the attitude of Abigail was surely very special. Notice how she not only went prepared to correct the evil her husband was guilty of, but she was even willing to take the blame for him (I Samuel 25:28). She was knowledgeable about the current events of her day and how they related to David (I Samuel 25:29-30). She knew when to hold her tongue and when to speak out (I Samuel 25:36). And, she understood humility and diplomacy (I Samuel 25:41). So. David married Abigail... along with another lady; Ahinoam.