How do you tell when your parents do not love each other anymore?

If your parents were once a couple in love, you can tell by the difference - for example, if they used to kiss in front of people and don't do it anymore, or if they used to held hands, or hug themselves in front of people and have halted doing so. Then there's the fight-isolation sign. Some couples show their crisis by fighting a lot (with or without escalation) while others go in some sort of mute state, when both or one of them get silent and isolated, in other Words, don't even consider sharing their/its time and thoughts with the other, and ignore (is indifferent to) whatever the partner does or says. If this not knowing or not being sure gives you anxiety or sadness, talk to the parent with whom you feel more in tune. Ask, clearly. But don't comment. Don't criticize. What goes on between a married couple is too complex and deep for anyone to interfere (needless to say judge) without their permission. There's always something only themselves know and won't ever open to you - which doesn't mean they don't love you or don't cherish you. Always remember: parent's love has nothing to do with couple's love - these are two different worlds with two different set of rules.