So what does all this have to do with marriage? Pretty much what you’d expect. The new regime wants as many new purebloods as they can get, so they really want all the purebloods to be married to purebloods. Including the gays and lesbians. Wizards don’t usually go for that kind of discrimination, but they want babies, so the purebloods had better all get busy. Taking a lover on the side is usually tolerated if you toe the line otherwise.