I think people have missed that it's obvious the abusive aspect of the relationship would not have continued following this, just because it wasn't shown to us that it had because of where it ended. The trust issue, I believe, came from Sayumi being insecure regarding the sincerity of Jun's love, stemming from being repeatedly shot down in high school, which was solved following the scene in the park. Would have been nice to see how the relationship had become healthier, but oh well. What we had was nice, and I'm a sucker for a happy ending.
I giggled at the bit about the relationship beginning anew as I was listening to 'Wheel of Time', and it just got to the 'keeps on spinning, there's no beginning' part, so you know, ha, slight relevance to each other. I have low standards for comedy (why I've never said a funny thing ever). I once laughed at a Frankie Boyle joke as proof.