Your comments about your husbands vasectomy reminds me of what our family Urologist taught me when my husband had his vasectomy done. The doctor said 'The human body is constantly working to heal itself.' That is why some vasectomies fail and have to be redone.
If memory serves me, after my husband healed from the procedure, we had to purge the sperm that were already in his system (using alternative BC of course) and then have a specimen of his semon tested one month post procedure, and then tested again at six months post procedure, and then again at one year post procedure just to be sure that his body hadn't found away to put itself back together. (I was the lucky one got to take the specimens down each time. But, I was motivated, so I'm not complaining.)
Anyway, my point here is to remind and inspire everyone about how the human body is constantly working to repair itself. Failed vasectomies are a perfect example of this fact.
Best Regards to all,