Yes it's normal if you consider the timeline of 2-5 years to heal from an A. They were in luuuurve. That's not Love. I rarely quote the bible but I often refer to 1 Corinthians 3 for an idea of what love is.
"4 Love is patient, love is kind. It does not envy, it does not boast, it is not proud. 5 It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. 6 Love does not delight in evil but rejoices with the truth. 7 It always protects, always trusts, always hopes, always perseveres."
One of the ideas that I have a hard time reconciling in my mind is that my husband actively pursued a relationship with someone else while he was still in a relationship with me. How immature is that? It's baffling. That's NOT love, that's denial, immaturity, self-centeredness and self-delusion, it is self-destruction, deception and manipulation but don't call that love.