When you spend more than one day apart, your heart gets a slight ache. You manage it because you know that when you two reconvene you'll have so many stories to tell each other over cheap whiskey and leftovers so it's totally worth it.
You sometimes realize the uninterrupted eye contact you two share is making people around you feel uncomfortable. You may be ecstatic you've found your soulmate, but that doesn't necessarily mean you want to accept the life of a total social pariah. Try to hide your unbearable happiness so the rest of us can eat, OK?
And beyond just the physical connection you two enjoy, the mental connection is really where it's at. You two can talk for hours and hours about whatever. You might know every little thing about him or her, but still find small details about them far too fascinating.
Alright, so you may or may not believe in past lives or the longevity of souls, etc. etc. But there is something sort of freaky about feeling a distinct knowledge of your soulmate from before. Like before before, like a past life before. It's weird, we know. But sometimes you see them or feel them and somewhere deep behind your heart and lungs, you know this person is familiar to you in a way that is beyond comprehension.
Again, it's mushy, but you want to do literally everything with your soulmate. Shower, drink tea, drive around, do your taxes, watch a movie, go to Europe, go to theme parks, have Christmas, read a book, look at stars, do nothing. If you weren't so in love, you two would annoy even yourselves.
You know when you see a kitten that is so cute you hug it just a bit too hard? Maybe it even lets out a little kitten squeak and you're immediately terrified you might love it so hard it'll break? Yeah, you feel that way most of the time with your soulmate.
Even when you two need to get some work done, you want to do it together. Being able to spend time in the same room with another person while existing in your own world, touching the edges of theirs, is something magical.