Yes," said he, smiling. "You are better placed here; very fit for a wife, but not at all for a governess. But you were preparing yourself to be an excellent wife all the time you were at Hartfield. You might not give Emma such a complete education as your powers would seem to promise; but you were receiving a very good education from her, on the very material matrimonial point of submitting your own will, and doing as you were bid;" and if Weston had asked me to recommend him a wife, I should certainly have named Miss Taylor
Quoted from Emma by Jane Austen
What does he mean by "on the very material matrimonial point"? And what does "on" function as here?