Okay, well it may be, as you say, ruins just aren’t your thing. It’s worth trying it after a few days denial vs recently having cum and see if that makes a difference.
Also try forcing yourself to masturbate for five minutes after your ruin, it may just reset things enough for the horniness to kick back in.
But otherwise, you’ll just have to work hard to only edge and not go over… because we don’t want orgasms ruining everything, do we 😉
Merry Christmas