Narrated 'Aisha :

I said, "O Allah's Apostle! Suppose you landed in a valley where there is a tree of which something has been eaten and then you found trees of which nothing has been eaten, of which tree would you let your camel graze?" He said, "(I will let my camel graze) of the one of which nothing has been eaten before." (The sub-narrator added: 'Aisha meant that Allah's Apostle had not married a virgin besides herself .)

حَدَّثَنَا إِسْمَاعِيلُ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنِي أَخِي، عَنْ سُلَيْمَانَ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ قُلْتُ يَا رَسُولَ اللَّهِ أَرَأَيْتَ لَوْ نَزَلْتَ وَادِيًا وَفِيهِ شَجَرَةٌ قَدْ أُكِلَ مِنْهَا، وَوَجَدْتَ شَجَرًا لَمْ يُؤْكَلْ مِنْهَا، فِي أَيِّهَا كُنْتَ تُرْتِعُ بَعِيرَكَ قَالَ " فِي الَّذِي لَمْ يُرْتَعْ مِنْهَا ". تَعْنِي أَنَّ رَسُولَ اللَّهِ ﷺ لَمْ يَتَزَوَّجْ بِكْرًا غَيْرَهَا.