h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Hi,
I was directed to this page by some very helpful peeps This is my story ~ my boyfriend is fighting in Afghan with the British forces, he's been there 3 months now, and has another 4 to go, it's our one yr anniversary next weekend and unfortuantely he won't be here. I can imagine that what he is going through must be extremely difficult, and I want him to know how much I love him as we both believe that we are soulmates. I would like to get the following phrase translated into Latin if poss & have it engraved on to a bracelet for him. I would be so grateful if someone could help ~

Soulmate ~ together in heart, body, mind and soul for all eternity.

Thank you

The main part is straightforward:

together in heart, body, mind and soul for all eternity.
"corde, corpore, animo et spiritu in aeternum coniuncti"

But I'm not sure what to do with "soulmate" as it is in no Latin dictionary I've seen.

Semper una is always together. That's the closest I can find.

thank you ever so much for this, i appreciate it greatly, will be going to get in engraved tomorrow. i think it's quite sad that latin isn't a language that people would like to use more often. there's a certain sense of age about it that strikes me.
The translation for soulmate - is there any other word that would describe the same perhaps ?

thank you for this, you've all been such a great help.