Even the healthiest long-term relationships have their fair share of ups and downs. So how do you know when youre wading through some choppy-but-temporary waters versus when the relationship is seriously in decline?

We asked couples therapists to share some of the not-so-obvious signs a marriage may be heading toward divorce. Heres what to look out for, according to our experts:

1. Youve stopped fighting with each other.

This one may seem counterintuitive at first because many people believe that less arguing is indicative of a relationships strength, said Los Angeles marriage and family therapist Abigail Makepeace .

But when a couple no longer has a desire to hash out their issues, it may indicate theyve become emotionally disengaged.

The absence of conflict might suggest that one or both partners no longer see the relationship as worth fighting for or, in a broader sense, as worth saving, Makepeace told HuffPost. If one partner stops complaining without any resolution to the underlying issues, it could be a sign that they have given up on the relationship and are preparing to leave.

West Los Angeles clinical psychologist David Narang said he has observed this while working with male patients in heterosexual marriages. At first, their wives may express their sadness and anger when they feel deprived of emotional connection. This generates conflict and gets the husbands attention. But when the wives stop sharing their frustrations, the husbands are often relieved. They figure all is well in the marriage but this assumption is an error with tragic consequences, Narang told HuffPost.

In this situation, the wife has not calmed because all is well, but rather because she has given up, is disengaged, and is beginning to live an emotionally separate life, he continued.

This makes the marriage extremely fragile because she has given up getting nourishment from the marriage, and thus, she has less and less investment in it. As such, she is much more likely to react by filing for divorce when something goes wrong, he said.

2. Your lives have become more and more separate.

Its normal and healthy for partners to maintain some independence within a marriage whether thats having their own friendships, career aspirations or hobbies. A growing sense of division, however, can be a warning sign that the marriage is in decay, Makepeace said.

In couples experiencing trouble, the trend toward spending more time apart may not just reflect a healthy balance but rather a preference for living separate lives, she said. This increasing separation often points to a deeper disconnect and a diminished desire to share experiences together.