Asalamu Alykum Ilker
First point to note is that marriage cannot happen unless both the male and the female agree to the marriage. There is no force in marriage.
Second point is that marriage is lawful between believing women and believing men. Even marriage is lawful between believers from the People of the Book and the believers of the final revelation(Quran).
2:221 And do not marry polytheistic women until they believe. And a believing slave woman is better than a polytheist, even though she might please you. And do not marry polytheistic men [to your women] until they believe. And a believing slave is better than a polytheist, even though he might please you. Those invite [you] to the Fire, but Allah invites to Paradise and to forgiveness, by His permission. And He makes clear His verses to the people that perhaps they may remember.60.10 ...And if you know them to be believers, then do not return them to the disbelievers; they are not lawful [wives] for them, nor are they lawful [husbands] for them....
5:5 (Lawful unto you in marriage) are (not only) chaste women who are believers, but chaste women among the People of the Book, revealed before your time,- when ye give them their due dowers, and desire chastity, not lewdness, nor secret intrigues if any one rejects faith, fruitless is his work, and in the Hereafter he will be in the ranks of those who have lost (all spiritual good).That being said and taken into consideration the above then the meaning of what your right hand possess has a different meaning than simply wedding any captive or women. This should be viewed as women who voluntarily left their previous lives and husbands and adapted and became believers. They do not need to be divorced. This is supported by the following verse 60:10
4:24 Also (prohibited are) women already married, except those whom your right hands possess: Thus hath Allah ordained (Prohibitions) against you: Except for these, all others are lawful, provided ye seek (them in marriage) with gifts from your property,- desiring chastity, not lust, seeing that ye derive benefit from them, give them their dowers (at least) as prescribed; but if, after a dower is prescribed, agree Mutually (to vary it), there is no blame on you, and Allah is All-knowing, All-wise.060:010
"O you who have believed, when the believing women come to you as emigrants, examine them. Allah is most knowing as to their faith. And if you know them to be believers, then do not return them to the disbelievers; they are not lawful [wives] for them, nor are they lawful [husbands] for them. But give the disbelievers what they have spent. And there is no blame upon you if you marry them when you have given them their due compensation. And hold not to marriage bonds with disbelieving women, but ask for what you have spent and let them ask for what they have spent. That is the judgement of Allah ; He judges between you. And Allah is Knowing and Wise." Please see the article below for a detailed explanation [1].
Peace
[1]. Also (prohibited are) women already married 4:24http://quransmessage.com/forum/index.php?topic=1260.0