Re: Which Prophet married only ONCE in his lifetime?
From what I know, most Prophets (AS) had one wife at a time. That is also according to Quran, as in Quran, Allah says that it is very unlikely that a man (human) can do justice if he has two or more wives, and obviously, Prophets were God fearing humans.
Anyhow, few had more than one wives at one time, but they were those few who at the time had no ‘love, affection and emotional attachment’ with their multiple wives (as their attachment at the time was only for Allah) … hence for them, it was no problem treating wives equally and justly, with whom they had no love, no affection, nor any emotional attachment.
Example: Prophet (SAW) had both phases. Phase of love, affection and emotional attachment with his wife hence only one wife, Khadija (RA), and then, phase of no ‘love, affection and emotional attachment’ to his wives, hence multiple wives.
Prophet (SAW) loved and got emotionally attached to Khadija (RA) and as long as she (RA) was alive, Prophet (SAW) did not marry anyone.
Aft the death of Khadija (RA), Prophet (SAW) did not loved or got emotionally attached to any of his wives, and thus married many. Lack of love and emotional attachment to his (SAW) later wives can be seen from two verses in Quran, where it shows that Prophet (SAW) was willing to even divorce all his later wives and Allah gave that message to all his wives (through Quran) showing Prophet (SAW) lack of love and emotional attachments with them.
Surah 33: Ayah 28-29 (Yusuf Ali): O Prophet! Say to thy Consorts: "If it be that ye desire the life of this World, and its glitter,- then come! I will provide for your enjoyment and set you free in a handsome manner. But if ye seek Allah and His Messenger, and the Home of the Hereafter, verily Allah has prepared for the well-doers amongst you a great reward. (Surah revealed around 5 Hijri)
Surah 66: Ayah 5 (Yusuf Ali): It may be, if he divorced you (all), that Allah will give him in exchange consorts better than you,- who submit (their wills), who believe, who are devout, who turn to Allah in repentance, who worship (in humility), who travel (for Faith) and fast,- previously married or virgins. (Surah revealed around 7 Hijri)
Obviously, with love, affection, emotional attachment and children from Khadija (RA) and all her (RA) support to him (SAW), Prophet (SAW) would never have thought of divorcing Khadija (RA) neither Allah would have given message to Khadija (RA) mentioning such possibility. Such message mentioning possibility of divorce, can only be given to wives with whom a person has no love, affection, or emotional attachment.