There's stigma attached to such relationships.
There are several reasons why people aren't okay with romantic relationships involving an older woman and a younger man.
- Some say men married to older women eventually get bored and stray. The woman would hit menopause and old age earlier than the man, which would only accelerate the straying process.
- Younger women symbolize youth so older women = lack of youth.
- Most men are programmed to see older women as 'mother figures' or 'sisters'. Anything that goes against social conventions is largely regarded as abnormal and/or unnatural.
- In some cases, older women are divorcees or are 'undesirable' for other reasons.
- It is assumed that older women come with emotional baggage. Therefore, the relationship wouldn't work. They also come with a lot of experience and have high standards, which the younger partner wouldn't be able to live up to.
- Women mature faster than men (5-11 years as per scientific studies). Hence, (according to some) women should marry men who are 4-5 years older than them. Younger men are considered emotionally immature.
- In some cases, generation gap. For instance: A 30 year old woman enjoys watching 'Johnny mera naam' whereas her 20 year old boyfriend prefers to watch 'Humpty Sharma Ki Dulhania'.
As you can see, the society is full of double standards and bigotry. On a different note, my father's been married to my mother, who is older than him by 2 years, for the past 30 years.