According to studies this is the ideal difference between age and relationship

In many cultures, heterosexual relationships in which husband is greater than his wife are still more prevalent. In such relationships, there is a common age gap of 2 to 3 years.

Meanwhile, according to an Australian study, it turns out that:

Heterosexual couples with major differences in age experienced a faster decline in their relationship satisfaction in the first six to 10 years of marriage than couples of similar age.

Couples aged between 1 and 3 years (with a husband older than a woman) were more common and had the highest levels of pleasure.

Rhesis relatively low for couples of between 4 and 6 years and continued to decline for couples at a rate of 7 or more years.

A 2015 Korean study found that changes in age in long - term relationships can affect each partner's chances of suffering depression. In particular, he found that couples at the same age had the lowest rate of depression, while couples with a age gap of 3 years or more had slightly higher rates.

In brief, research seems to indicate that in many cultures, a age difference of 1 to 3 years is considered ideal, but some researchers suggest that even a relationship with a age difference of less than 10 years will bring more satisfaction.

However, numbers rarely tell the complete story when it comes to love. It is possible to be much older or younger than your partner and to have the right relationship for you.

Regardless of age, some factors related to the success of relationships include:

Education
Financial Security
A Desire for Children
A character
Communication
Personal Matters
With other family members
Emotional Intelligence
A Pleasure in Sexual Life

A age difference is just one factor that can affect your relationship and does not necessarily mean that it is the factor that creates or destroys a healthy relationship.