If the age difference between partners is within 16 years, such a relationship may well be successful and lasting - since both partners belong to the same generation. But the difference above is a potential time bomb, because in this case it will be more and more difficult to seek mutual understanding, even if everything was great at the beginning of the relationship. After all, a big age difference often means a different look at familiar things, as well as relationships. In addition, partners may have different expectations regarding each other.

However, a significant age difference between partners does not doom the marriage to failure - it only means that both will have to make more efforts to come to an agreement.
First of all, the emotional maturity of the partners affects how harmoniously relations will develop, and it does not depend on the number in the passport. If two mature people who managed to realize themselves decided to unite in a couple, then most likely there really is a real spiritual unity between them, harmony, mutual understanding, and the ability to constructively resolve conflicts, support each other. In this case, the age difference does not matter.

However, consider the most typical points.

Husband is significantly older than wife

In fact, this is a rather traditional relationship model that came from previous generations, when it was economically beneficial for a young woman to marry a mature, wealthy man. Today, such marriages are also far from uncommon.
What pushes men, mostly over 40s, who may have more than one marriage behind their backs, children, obligations, etc., to enter into a relationship with a younger woman? Love? It is quite possible ... But most likely the reason is much more prosaic. A young partner for a mature man is often an attempt to make up for what was never realized in previous relationships. To feel important, aware, competent, which he may not have always felt in previous relationships, as well as the ability to take care of a less experienced partner. And also to feel the second youth and make sure that “I’m still hoo-hoo” and “old age is not about me at all, about my peers - yes, but definitely not about me!”. It can also be an escape from the complexes associated with the ex-wife, the age difference with which is much less or absent altogether, or problems of a sexual nature or health. However, if such relationships do not “slide” into parent-child relationships, then everything is in order - there is a chance for duration and mutual understanding. In a relationship where there is a big age difference, the older partner seems to want to rejuvenate, feels uplifted, and the younger one, accordingly, inspires him to accomplish.
For a woman who enters into such a relationship, things may not be so simple either. At the beginning, it can burst with pride: “A man with experience who has seen more than one woman on his way, and now chooses me! How valuable and important I am, now not only in my eyes, but also in his. But often a young woman, to whom an older and, accordingly, more wealthy partner gives everything ready, runs the risk of abandoning her own development and self-realization, having all the opportunities for this. She is mostly content with what she already has and is unlikely to attempt to achieve anything herself. Often such women can call their life a "golden cage", however, do not take any steps to get out of it.
The woman is older than the man
Recently, there are more and more such families. Mostly these are marriages between already realized, self-sufficient, financially independent women and young men. Each of the partners has its own benefit in such a relationship. A mature woman may be more sexually attracted to a younger partner than a peer. Often such women “take guardianship” of their young husbands: they help financially, push them up the career ladder, teach them how to cope with a wide variety of life situations, often in this way realizing their maternal instinct, which may not have been realized before. In such relationships, as a rule, the woman is the leader, and the man is the follower, and if both are satisfied, then everything is in order, the couple can live long and happy years in harmony and mutual understanding.
A young partner in such a relationship has the opportunity, first of all, to “grow up”, “grow up”, gain life experience, feel like a man. Often these are men from families where not everything was smooth in relations with their parents, in particular with their mother, so relationships with an older woman are a subconscious desire to catch up with something in these relationships. For example, to go through a symbolic separation, which, for certain reasons, was never implemented. If so, then the relationship is a younger man - a mature woman sooner or later will end in divorce - because from the very beginning they were based not on mutual feelings, but on the subconscious "acting out" of destructive parent-child scenarios.
Another point characteristic of such marriages is the woman's fear of growing old, and as a result of this, the fear that sooner or later the young husband will leave her for the sake of, for example, his peer. Unfortunately, this happens quite often. Although more common are cases when a partner remains “under the wing” of his wife, taking her care and guardianship for granted. In this case, the main thing for a woman is not to turn a blind eye to the true state of affairs and either leave the relationship where she is used, or leave everything as it is, if it suits her.