Soul mate doesn't equal co-dependence. A person who relies on the idea of the existence a soul mate is co-dependent. People treat their lives like their only mission is to find their soul mate and then everything else will make sense. It doesn't work like that. Existence is a lot more complex than that.
I think you're missing chemistry with your wife. You can love someone very much, but still fail to have strong chemistry. Chemistry is a rather instinctive feeling and each person's personal chemistry reacts different to everyone else's. Like I said, you can still love and respect this woman for a number of reasons (she's comfortable, sensitive, caring) but that isn't necessarily enough to make you feel passionately about her.
And to answer your question, it depends. Some people are lucky enough to find a person with the same growth rates and patterns so that they always manage to find themselves on the same page. I think that's kind of the realistic side of a soul mate situation. More often than not because we're all so different we have to make compromises for the people in our lives. My boyfriend and I have to do it all the time. I love to dine out at nice restaurants while he's perfectly happy to eat fast food. We have to meet in the middle. We're both also pretty easy-going so we're comfortable being frank and honest when we're pissing each other off. We don't have passive-aggressive fights, we don't lie to each other, and we can argue and get over it in about 5 minutes. Because we know that there's way more important things than holding a stupid grudge or being right all the time.