I don't have any couples in my comic at the moment (the last happily married couple died tragically), but I hope it's okay to post some of my faves:
This is a really cute high school romance. Sarah and Castiel are classmates and met during an awkward school project where they had to take care of a doll, simulating it was a baby. Really recommend cheching it out! It's a webnovel, very well written and episodes are bite sized.
A human and a cosmic being fall in love. They are so cute I'm still hoping this isn't going to end in tragedy :C
And I know this is a premium comic so after a few episodes it's gonna charge you, but I got to read it during a weeked it was free and the story is really sweet. Also scifi, which I like :3