is an airborne infectious disease which spreads by droplets which are generated during talking, coughing, laughing, sneezing
and even normal breathing. Closeness increases the chances of spread. However if your fiancee is taking proper treatment, he is probably not infectious as a person becomes non infectious as early as 2 weeks after starting antitubercular treatment. However you should get yourself screened for TB if you have known him since before he was started on treatment.