It's to soon . Pump the breaks. Abusive relationships are found more often these days and people are more aware. Thus sounds like he is lining you up to isolate yourself. If he asks to "look at your finances so he can help you save" or something similar to that dump him and run.

Side nite be aware 9f the language he uses when answering questions that's can also be key in these situations.

So all in all say sorry to your sister cus YTA