I see that I am. You are not saying, "Which is stronger bond, marriage or Christ?" You are saying, "What is stronger, marriage or Christian brotherhood (fellowship)?" I knew that a few days ago when I answered the question, but in returning to the thread yesterday, I forgot the intent of the OP. Sorry.
In that case, I must still choose marriage. As we are not to be unequally yoked, our marriages are to be to our sisters or brothers. We have that eternal bond with our spouses, as surely as we have that eternal bond with our brothers and sisters in Christ. They are both our brother or sister, and our wife or husband, which is (as I said originally) second only to Christ in commitment and spiritual bonds.
Sorry I confused the thread and sort of derailed it.