Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear questioner, we would like to thank you for the great confidence you place in us, and we implore Allah Almighty to help us serve His cause and render our work for His Sake.
Answering your question, The Permanent Committee for Scholarly Research and Ifta’, states:
According to the most correct opinion maintained by scholars, if a man touches his wife directly, this does not nullify wudu’, whether he touches her lustfully or not, for the Prophet (peace be upon him) kissed one of his wives and went for prayer without performing wudu’ again. Moreover, whenever the Prophet (peace be upon him) made prostration while standing for optional Prayer at night, he used to touch `A’ishah (may Allah be pleased with her) with his fingertips to withdraw her legs due to the narrowness of the place, then he would prostrate. It would also impose a lot of hardship if wudu’ was required whenever a man touches his wife, so if it really nullifies wudu’, the Prophet (peace be upon him) would have explained it.
As for Allah’s Saying in suraht Al-Nisa’ and Al-Ma’idah: “…or you have been in contact with women (i.e. sexual intercourse)“ this refers to conjugal intercourse, according to the more correct of the two opinions maintained by scholars. This was reported by some of the Companions of the Prophet and the Followers (the generation after the Companions of the Prophet) may Allah be pleased with them all.
Allah Almighty knows best.