Mercury in the 7th house of a person's natal chart indicates someone who is communicative, often talkative, and difficult to interrupt during a conversation. The 7th house represents partnerships, including close friends, marriage partners, business partners, and the person's level of popularity.
With Mercury in the 7th house, the individual sees the world as an exchange of information, an opportunity to share and discuss various topics. They may find success in intellectual pursuits through partnerships, and it is important to them that their partner shares similar interests and intellectual capabilities. They value an educated and well-read partner.
Accordingly, they tend to choose partners who are intellectually developed, often significantly younger or appearing youthful. This positioning of Mercury can sometimes suggest an early and unstable marriage, with more serious relationships developing later on.