
A few years ago, when I first heard about MDZS (due to its popularity), I didn't know danmei or anything. When I read few chaps of mdzs, tbh, I didn't like the art style or understand the plot, which was SO confusing.
Now, mdz is one of my favorites, and I have official Danmei and Manhua copies at home.
If I could, I'd definitely punch myself for not reading it that time. ヽ༼ ಠ益ಠ ༽ノ

Depression made him horny!!

This is true for some people. Sex is their only way to get a boost of dopamine and serotonin.
I'm told that the high tou get from sex is several times more potent than the high you get from doing drugs. So yeah, it's not unusual for depressed individuals to exhibit high libido, sexual promiscuity, and deviancy.

From what I know, you're either bored or depressed that's why ypu mastubate or crave sex more than necessary--or you have sex addiction.
Rule of thumb when rubbing one out, if it's not getting in the way i.e. you procrastinate or push off your tasks to masturbate, you're probably alright. But if you're neglecting tasks and refuse to socialize in favor of sex/masturbation, you need to seek help
You should take care of your grandma instead of playing cupid (-.-)