FABIAN Maria writ The letter at Sir Toby's great importance; In recompense whereof he hath married her. (5.1.5)
Wow. This play is really interested in pairing off heterosexual couples, including Sir Toby Belch and Maria. The announcement seems to come out of nowhere, but if we think about it, it makes sense. Toby and Maria constantly engage in sexually-charged banter and Toby more than once tells us that he thinks Maria's wit and shrewdness are attractive.