What reaction should I have?

My girlfriend, whenever she takes long to respond, I usually assume she's busy, or something and think nothing of it,

When she replies, if I ask her why she took so long to reply she tells me and being too nosey or controlling,

But when I just Carry on the conversation without any mention of it, she started telling me that I act like I don't care and would say it's probably because I have other girls to keep my company
What reaction should I have?
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