The tether is very real. My first dedicated exploration ship was my Freagle (I know...), and I got homesick after 1000 ly. Of course, combining the Eagle's tiny range (I couldn't afford a nice FSD) with my lousy exploration skills meant it took me days to go those 1000 ly...
My first long distance trip was in a Cobra Mk III, and I got homesick after about 10 kly. My exploration skills were better, but my time to play was very limited, so it took over a week to get those 10 kly. I could just feel the distance from home.
The next trip that exceeded those 10 kly was Distant Worlds. I think having contact with other commanders out in the black helped stave off homesickness, but I'm still happily tooling around out past the 65 kly line and feel utterly at home.
One of the things I really appreciate about ED is that there are no teleports. If I'm out exploring, I very explicitly can't be back in the bubble doing bubble things. 65 kly out means another 65 kly to return. It really gives a hint of what exploration must have been like for folks like Shackleton. Without the cold and starvation, of course...
One of the interesting things that Distant Worlds has given us as a community is a whole flock of experienced deep space explorers who have a taste for meeting people out in the black. There are now a handful of expeditions with deep space meetups going on. If you're homesick, maybe see if there are other explorers within a few days travel of you. 3300 and 3301 were very definitely the age of explorers. 3302 is shaping up to be the age of expeditions.