Dear Sister,
Wa alaikum assalam
In my humble opinion from a Quran's perspective, there is no support for this practice.
A 'Nikaah' is not complete until it is consummated (4:21)
(afda ba'dukum ila ba'din - gone one of you to another). The solemn covenant (Meethaqan Galezaan) is but one part of the marriage bond. In this
'solemn covenant' there is arguably
no room for
'trial by courting'. The intention is to be married indefinitely and to seal the bond quickly with consummation.
Until Nikaah is completed, arguably normal Islamic etiquettes need to apply as if the parties were unmarried. One can only imagine what licence this would give couples who under partial 'Nikaah' would think they are able to do all else apart from intercourse. Arguably, such a concept can only be seen as a transgression to God's guidance.
I hope this helps, God willing.
Joseph
REFERENCE:[1] NIKAAH - THE CONTRACT OF MARRIAGEhttp://quransmessage.com/articles/nikaah%20FM3.htm