When a planet is retrograde it appears to back up in the sky, relative to our position on earth. This backward motion creates a Disruption in the things produced by the planet, both as a natural karaka and as a house ruler.
Venus is the karaka of relationships, happiness and compromising with others to grow those things. As a house ruler, based on the ascendant, Venus will rule different houses based on where Taurus and Libra fall from that ascendent.
When Venus goes retrograde in the sky, it is a time when our relationships can be strengthened or weakened, based on how we handle the adversity and the disruption that is produced. But we should expect some confusion and reflection on our relationships during Venus retrograde cycles.
In the natal chart, when Venus is retrograde, there will be hesitation about how to move forward with relationships, and whichever houses Venus rules from the ascendant.