Look up demonic posseasion/obsession by father Ripperger on YouTube. What he says, and in my experience it's true, is that demons can control people's perceptions, and turn an innocent thing into a dig.  The example he gives is a wife, on her husband's birthday who wants to bring him breakfast in bed. So she goes and asks her husband when he's going to wake up.  What the husband hears, however, is "why are you so lazy? Why don't you ever do what I want you to do? She thinks you're terrible and evil" Unfortunately he's your boyfriend and not your husband. If he was your husband (and I think you have to be in the state of grace, but I'm not sure) then you could say a binding prayer (if you're cohabitating you're not in the state of grace, unfortunately).  As the girlfriend, the only advice he gives is to really consider if this is the type of relationship you want. The choice is yours, no judgment on my side.  Good luck, and let me know if you want me to dig out that lecture or if you can't find it. God bless.