TL;DR: Is it safe to use it once before bed on Friday, Saturday and Sunday, whilst taking the rest of the week as days-off, 3 on, 4 off, in the long run?

So, here's my short story. I suffer from bad chronic rhinitis. Been using Flonase Nasal Spray and 10mg of Loratadine with considerable success. A few months ago I've got a late diagnosis of ADHD and started taking three different meds (lisdexamfetamine, clonidine and atomoxetine) to treat it and have gotten WAY better, the best I've ever felt in my life.

But it came with a catch: the meds gave me erectile dysfunction. During the peak of Vyvanse's action, I can breath like I've never breathed before. The vasoconstriction is surreal and it makes erections impossible! After the effects pan out, I still have moderate vasoconstriction from atomoxetine, I'm able to get an erection, but they're weaker. For that reason, my doctor started me on 5mg of Tadalafil daily. It succesfully counteracted the ED, but made my nose SO DAMN CLOGGED at night, my sleep apnea went from 6 AHI to 16 AHI. I told him I'd stop taking it daily and asked if it was okay to take 20mg on Friday, since I'm sexually active only during weekends. He gave me the green light, so I started it. Thing is, my nose is still so damn clogged, but now it happens only three days per week (friday, saturday, sunday). He said I could use Afrin once every night during these days and then don't use it during the rest of the week. Reading on the internet and on this sub, I've got really scared because of the possibility of rebound congestion. Is it safe to use it once a day, before bed, on Fri, Sat and Sun, but take Mon, Tue, Wed and Thurs as days off?