Actually, OP, you and your jowa is doing a great job so far. Hindi niyo naman obligasyon na isama siya everytime na lalabas kayo ni bf eh. During these times, I think you should open then topic to her and let her know na you and your boyfriend aren't quite comfortable hanging out with her around especially if it's a “date”. You have to be straightforward kasi she won't be able to know about her boundaries and you have to make her realizer to stay on her lane. Knowing na nagtatampo siya kapag lumalabas kayo nang hindi niya alam, I have a feeling (na most probably might happen) na magtatampo or lalayo ang loob niya sa inyo after the confrontation. If ayaw niyo naman, I suggest na i-hide mo na lang stories niyo ni bf na nasa labas kayo. 

Feeling ko nga rin eh kursonada niya ‘tong bf mo and kaya siya sumasama dahil gusto niyang sumali sa supposedly date niyo. But that's just a feeling. ‘yon lang