Making netorare / cheating stories be this romantic makes me feel a little conflicted, if it's this sweet, did it need to be netorare in the first place? Honoka and Matsubara have been keeping this affair for a while now, Souta has grown a little.
This sequel reinforces the fact Matsubara is a better partner for Honoka, as she outright claims at the end Matsubara made her feel like being a mother and child care is a fulfilling thing, unlike her absolute piece of a shit husband who makes Honoka feel like a servant, Matsubara is a partner that actually makes Honoka feel cared for and wants to raise her little boy Souta together, Matsubara reassured Honoka she will by her and Souta's side for many years till he grows into a man.