Well, children are a big factor, but there are others.
Right now I am separated and both us give reconciliation no more than a 5% chance. My wife of 13 years had an EA while we were together and, I assume, it is now a PA following our separation. But it is possible. The first thing is that we have never stopped loving each other. That is fundamental. We respect the person within the actions. Second, we are both starting to take ownership of where our relationship went wrong (not the affair, but the prior breakdown). Third, you come to a point - or at least I have - where you just see the frail, flawed, deeply hurt child who is still there in all of us.
When I feel angry with my WW, I picture her at seven years old, rejected by her dad. I see her in her sixteenth year, abused by an adult then discarded. I see the pain I caused her (as we all inevitably do) and I see her struggling to find her own identity. How can I hate that child? That is who she is at the deepest level: We all are. She didn't plan to hurt me. She doesn't want to hurt me now. I forgive her. I profoundly let her go and wish her well.
It may be that we can never live together again. Or we might just regain that spark. I might never be able to bring myself to trust her, and she might never see past my faults. Who knows?
Recently we have shared some brief good moments. An uplifting text here, a hug there, just a smile perhaps. The way I see it, if there is to be any chance we have to start again from scratch. I force myself to look at her as I did when we first met. No expectations, no deadlines, no ultimatums, no baggage. Just two tiny specks on this lonely planet, trying to connect, trying to live as best we can. No cake eating though. She is on benefits and finding things hard. That was her choice and she needs to live with it.
It is a cliché, but letting go and forgiveness are the only way to live FOR YOURSELF. Once BOTH partners recognise that, who knows what will happen.
Like I say, a 5% chance for us at best. But right now it doesn't matter. What I know from the depths of my being is that neither of us will ever share with anyone else the same depth of passion, trust and love that we once had - and two wonderful children. We are linked by an unbreakable love forever.
Good luck!