So, about how Soulmates work here...

Lance said he had several, correct? Well, in this world(story whatever) every person, alien, being, thing, has one true soulmate. They also have others. But you see, the universe ig tests them or something with each new or old soulmate. The person has to find their true soulmate, amongst all those others who aren't. So basically, they're true love, the one they are/were meant to be with, stuff like that.

Other questions you might have: 

What if their true soulmate dies?

Well, if their true soulmate dies, they will feel the weight of their absence on their mind, body, and soul. Kinda like being depressed all the time. Then after a long while, they will find their next true love or one they are meant to be with. Actually, there can be more than one true love or meant-to-be-one but only if one of the soulmates died. But that was rare. 

Sometimes, the soulmate would be reborn and met with their old soulmates again and would live happily ever after. Or at least that might happen. The world may cause problems and hardships, ones they will have to overcome and whatnot. So we really can't say.

What if the person is reborn but doesn't ever find or meet their old soulmate?

Well, they would either find a new one, like their old soulmate, and be with that person. Or they would die lonely ig.

Random info:

Sometimes people are born without their soulmates and die alone because they never had one or found the right one. It is sad really.

If you have questions, feel free to ask. But right now, I need to sleep so bye~ ^-^