It's a little too late in the day to be ordering a I don't hate you".— but it's never too late to say "
If you poke around the internet, there are a lot of fan-made Portal valentines to be found. But it's pretty hard to beat the official printable Portal Valentine's Day cards from Valve, released two years ago, in 2011.
There are six cards to be found on this free download (PDF), featuring GLaDOS, Chell, sentry turrets, a weighted companion cube and an intelligence sphere.
If you prefer something that can be emailed, Tumblr user Tealgeezus has created some adorable animated gifentines, featuring GLaDOS, an intelligence sphere, a sentry turret, a weighted companion cube, the space sphere and Cave Johnson's combustible lemon.
And if none of these options quite floats your Portal love boat, why not show you care with a home-made, deliciously unambiguous? Actually, why not a full, ? We'd probably steer clear of the fluffy mackerel pudding, though.