Order Sequence of Scenes
So I've been thinking that maybe the last few scenes were shown out of order, which sort of plays into the movie as a whole because the director chooses to show us bits and images of the entire relationship, rather than the whole thing.
Here's how I think it plays out in reality (as opposed to how it's in the movie):
1) Anna and Jacob meet in school, and fall in love
2) Anna has to leave for the UK, after she violates her school visa
3) Anna comes back to the US but is not allowed in because of her violation
4) Jacob visits Anna in the UK, but says it's like a vacation and not like they're together
5) During this visit, they seem to agree about seeing other people because it's hard to "stop and start again"
6) Jacob returns to the US and meets Katniss, Anna meets Simon
7) Both relationships get pretty serious, Katniss moves in with Jacob, Simon proposes to Anna
8) After seeing that it's not the same with other people, they talk in the parking lot of that club. This is probably spurred by the fact that Simon proposed, and it's a realization to Anna that she really doesn't want to spend the rest of her life with anyone but Jacob.
9) Jacob goes to the UK, and they get married
10) They have to wait 6 months for the marriage visa
11) Jacob comes back, and they're told there are marriage visa delays
12) They get into a fight, and Jacob has to eventually go back to the US
13) There is a long gap not shown in the movie between when they're denied the visa, and when they get the visa. All you're left with is the fight in the kitchen I believe
14) Anna gets the visa on her own in the UK
15) Anna leaves the UK for the US
16) Shower scene, the end