If we see spouse, partner then 7th house, 7th Lord is important, but Asc./Asc. Lord of Birth chart, Asc./Asc. Lord of D-9, 2nd House/its Lord, 4th House/its Lord, 12th House and its Lord will also play direct or indirect role.
Asc.- Self, 2nd House (nearest family-Kutumb), 4th house - family, happiness, 7th house spouse, 12th house (house of bed room) for Ladies in India we treat 8th house for Mangalya (but after marriage- age of spouse too.)
1st Promise, then dasha and finally transit of planets.
Nakshtra and its Lord is important, if we go in that deep then Analysis must be 1. from Asc, 2. from Moon and for marriage 3. Venus