this sentence is strange. should be: "we are glad to know she married David" or (less common, stranger): "we are glad to know of her having married David" usually we say: "we are glad to *hear* (that) she married David"

The sentence is perfectly correct, although there is a colloquial alternative. It's an extension of the gerund rule: marry - marrying Put a subject before the verb and you get: she marries - her marrying he marries - his marrying they talk - their talking I talk - my talking and so on.

Yes, this sounds strange, are you sure you quoted the sentence properly? Naturally, using "her having married" means it already happened. "We are glad to know OF her marrying David." could also mean the marriage is in the planning stage, ie. between the engagement and the marriage ceremony. "Her marrying David" would roughly equate to, "her plans to marry David". To agree with Ian, this particular phrasing may not be familiar to all native English speakers, and as a past event, we'd tend to word it as per his suggestions.

word of advice: don't marry

maybe "we are glad to know that she is marrying David" would sound better