How can I notice the slow boil before I'm cooked?

Annual relationship reviews help. Also: notice if you're less intimate, arguing more often, communicating less, or feeling lonely despite being together. If you're thinking about leaving frequently, the water's hot. Don't wait until it's unbearable.

At what point is the relationship unsalvageable?

When both partners stop trying—when conversations stop happening, resentment has built for years, and you've disconnected so far that you're strangers. Early intervention is key. Once you're fully checked out, reconnection is very difficult.

If I notice the slow deterioration, can I fix it?

Yes, if both partners recognize it and commit to change. Couples therapy, intentional date nights, vulnerability, and clear communication can rekindle connection. But it requires effort from both of you. If only one partner cares, the relationship will keep cooling.