Does watching one's children in the kitchen with one's wife or maid count as a divorce, and what if that recurs?

The answer to your question requires a clarification of two matters:

1. Your conditioning of divorce upon seeing your children with your wife in the kitchen with the phrase: "Consider yourself [divorced]" is an implicit divorce (kinayah). Since you intended divorce, it occurs if you see them, and your oath is dissolved by this divorce due to not repeating the oath's wording.

2. Your statement: "If I see my children with the maid in the kitchen, I will consider that like my children entering the kitchen with you" is understood as a promise, not a condition. No divorce is incumbent upon you as long as your intention was merely a threat.