Thoughts:
Harper is shitty. There are understandable reasons for the shittyness, but she’s still shitty. Breaking Riley’s heart was cruel, but I’m willing to chalk it up to being young and unclear about her own sexuality and going pretty easy on that one.
The way she treats Abby is much less excusable, imo.
First, she lied to her about being out. Dating a closeted person has a lot of potential pitfalls, and if you are dating someone seriously, I think they have the right to know that so that they can decide if they really want to go for the ride on your coming out roller coaster.
Second, she sprung the reveal on her in a way that didn’t really give Abby the option of backing out of the trip, and I think that was pretty manipulative.
Third, in order to maintain her own cover, Harper wanted Abby to play straight which adds another layer of discomfort and manipulation to the charade.
Fourth, she constantly ditched Abby, who literally knew noone there, so that she could hang out with old friends (including her ex). If Harper truly wants to spend the rest of her life with Abby, she should start incorporating her into it.
Finally, and I think most problematically, it’s pretty clear that without the Deus Ex Allison Brie that Harper would have kept this pattern going for a long time. She was always going to like the attention from the ex, was never going to want to disappoint her parents, was always going to want to wait just a little bit longer, and I think that is a recipe for a bad relationship.
I don’t necessarily think Abby should have run off with Riley (but I wouldn’t blame her if she did), but I just kinda think that Harper needs to get some of her own stuff together before she can be in the space to be a full life partner to someone else.