The speaker is deeply in love and a little afraid of losing it. The opening line admits that all the "cheesy" movie feelings are real, and the speaker feels them for one person. Being in that person's arms is described as finding a true home, and the speaker never wants to leave.
But the happiness has a shadow. The heart and the butterflies say one thing, while the speaker's brain says the relationship can't last forever. That tension drives the poem. The speaker wishes they could skip ahead in time to make sure this person is their future.
The second half focuses on time itself, which feels almost cruel: it races when the two are together and drags when they're apart. So the speaker wants to freeze a single moment and stay there. The last line, "but don't we all," shrugs the wish off with a wry, slightly sad honesty. The mood is tender, hopeful and bittersweet, written in a plain, diary-like voice that makes it feel sincere.