In my early 20s I would often (several weekends a month) leave my generally comfortable, warm house, spend my scarce funds on a train ticket from Manchester to Bradford, to then walk clean across the fucking city to a freezing cold, damp, uncomfortable house to see my then primary partner...
This would involve a walk through the red light district and some pretty unpleasant areas before and after that. The house was rented for him and a few others he worked with, to live in during the week by his employer, who clearly wasn't splashing out and they were buggered if they were going to...
NO heating, sitting on furniture that came out of a skip, house single glazed and draughty (But not enough to freshen it up from the damp, it smelt like a caravan)...
The sex was pretty good, but in hindsight, absolutely nowhere NEAR good enough for the effort it took to achieve it.
And he was on 40K a year, whereas I was on £45 a week. And he had to (generally, ish) come past manchester to get to his own home a couple of times a month anyway....
With the benefit of hindsight of course, the weekends i'd go there, were the weekends he wasn't coming home. The weekends he went home he'd be going out in his home town and enjoying his freedom to see whoever he wanted.
Just as I bought a young persons railcard (which had involved saving up...), the motherfucker moved down south to almost Bristol for another job, got himself a new primary partner and I was relegated to once in a blue moon when he'd be back up north at 'home'...
Ah, such a young fool was I.
All the other questionable and weird decisions I made in my twenties were sex related too, though unfortunately most involved significantly inferior sex.