My ex once put me on no-touch for a month, and at the end of it I went from orgasming in 7 minutes to 25 minutes, it’s about 15 minutes now usually, but it’s not ever fully recovered… any idea why or how to fix it?

Your body is telling you what you really need, and that is to not be allowed to orgasm at all. You don’t need fixing, you just need to be denied. Never orgasm and you won’t have to ever worry again about how long it takes.

Throw away the stopwatch, embrace denial, and all will be well with your soul.