I've had a similar problem.
My first boyfriend and mate felt completely like my soul-mate.
But it was not to be; He left me.
The next mate I had was brilliant. And the relationship was fantastic whilst it lasted, but in the end it fizzled out.
But still, to this day, I am still deeply in love with my first mate, and he knows it. My second mate was great, but he didn't
feel like my first. Sure, I was happy with him, but with my first there was just something extra special.
(I do not count my relationship with Donovan as a relationship at all, since it was so false and quick.)