Does merely thinking about marriage, accompanied by a slight, non-overwhelming, and non-erectile desire, invalidate the prayer?

Thinking about marriage and experiencing desire does not invalidate prayer or purity, unless it leads to the emission of madhy (pre-seminal fluid) or manyy (semen). A Muslim should lower their gaze, associate with religious people, and hasten to marry when able. They should also reflect on the Quran and the adhkar (remembrances) during prayer, and seek refuge in Allah from Satan, "Khanzab," spitting lightly to the left three times when he whispers. Imams should consider the congregants and lighten the prayer, and Muslims should be patient with the length of the prayer because it is among the best of deeds.