Why won’t my boyfriend (currently locked up) sext with me ever or initiate it?

PS: we communicate through email / the securus app.

I do it send really intimate detailed intense, fifty shades of gray type of stuff he used to send them back a year or so ago now he will pretend to have fallen asleep or even ignore me for literal days or he will send a half efforted sentence or two back … like he used to be REALLY into it but never initiate; he said before he doesn’t ask for sexy pics because he doesn’t want me to think that’s all this is about nowadays but he hints for sexy pics / videos a lot and he used to ask. But why doesn’t he like sexting?
Why won’t my boyfriend (currently locked up) sext with me ever or initiate it?
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