Originally Posted by NeonKaos
I hate to rain on your parade, Mono, but It's not clear how much time the op has been in a secondary relationship with the woman. The "partner" he refers to in the first sentence is the business-partner, the husband of the woman the op is involved with.
I do not see anywhere in the original post where it says how long the secondary relationship has been going on.
I thought OP was in a relationship with the husband, for ten years. Now I am thoroughly confused by who is dating whom for how long and what gender they are!