The ancient Jewish perspective is that there were seven aspects of the Godhead, which Revelation seems to tentatively substantiate in mentioning the seven spirits of God. I can therefore buy into the plainly implied trinity, or the plausible notion of a heptinity, but what you're suggesting includes man as part of the Godhead. Man, through his marriage to the lamb, becomes one flesh and spirit with Christ. However, we don't become God, or any part of God. This cannot be substantiated with scripture, even by inference. We are the wife. And although the wife is one with the husband, the principle is that we are still separate, though we are joined.
I do agree, though, that an argument could be made that the oneness of spirit we gain through the marriage taken in context with us being the body of Christ can potentially suggest this concept. It's like when Paul discusses laying with a prostitute. To join ourselves to a prostitute is to join Christ to a prostitute. So there is a possible contention for a true oneness of body and spirit.
BUT, that version of the argument would not make us a fourth component to the Godhead. It would make us one person with Jesus Christ, thereby removing man from the equation altogether. In other words, we go from four identities, three divine and one mortal and stained, to only three entities, all divine, with the mortal, stained identity slain and eradicated.
I like that you're thinking outside the box. I think it's an important exercise in expanding your overall understanding, assuming you accept the results of a comprehensive evaluation of your idea. But a quaternity doesn't really work.