My best friend was in this situation.
I'll tell you her experience without commenting on your own because it's for you to make your own mind up.
Friend had been SAHM for 20 years. Lovely home, two children, ok marriage but no excitement. Met another man and became absolutely infatuated, started an emotional affair which became physical without going all the way. She became giddy, somewhat reckless and completely carried away.
She confided in me and I told her straight that while I am her friend and always will be, I was disgusted at her behaviour, concerned for her DH and for her children (younger than yours, still at school) and also worried for her as, from what she told me, it was no way to happiness.
Fast forward. The marriage ended despite her DH's willingness to forgive and forget. She had a clean break settlement and bought a house, had to find work and also look after the children. The relationship with her ex broke down totally as it did with the DCs. The relationship with the OM also broke down, messily and ended.
Can't give away details of how things are now but I can tell you that she feels like a bomb went off under her life and she can't quite believe how things have turned out. She's constantly stressed, doesn't seem happy and is very concerned about the future. Her husband was also a 'good man' and she thinks she suffered a 'mid life crisis' which has left five people devastated.