Ruling on one who forbids marriage for himself

Firstly: 

It is not permissible for anyone to forbid that which Allaah has made permissible, such as women (marriage), food or anything else, because Allaah, may He be exalted, said:  

“O you who believe! Make not unlawful the Tayyibaat (all that is good as regards foods, things, deeds, beliefs, persons) which Allaah has made lawful to you, and transgress not. Verily, Allaah does not like the transgressors”

[al-Maa’idah 5:87]

Some of the Sahaabah wanted to be celibate and keep away from women, but the Prophet (peace and blessings of Allaah be upon him) forbade them to do that, and Allaah revealed this verse. 

Ibn Jareer narrated with his isnaad that Mujaahid (may Allaah have mercy on him) said: Some men, including ‘Uthmaan ibn Maz’oon and ‘Abd-Allaah ibn ‘Amr (may Allaah be pleased with them) wanted to be celibate, and to castrate themselves, then this verse was revealed.  

Al-Bukhaari (5074) and Muslim (1402) narrated that Sa’d ibn Abi Waqqaas (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) forbade ‘Uthmaan ibn Maz’oon to be celibate. If he had given him permission, we would have gotten ourselves castrated.  

Remaining celibate, getting castrated and regarding women as haraam are all haraam. This is turning away from the Sunnah of the Prophet (peace and blessings of Allaah be upon him), who got married and encouraged others to get married. 

Al-Bukhaari (5063) and Muslim (1401) narrated that Anas ibn Maalik said: Three people came to the houses of the wives of the Prophet (peace and blessings of Allaah be upon him) asking about the worship of the Prophet (peace and blessings of Allaah be upon him). When they were told, it was as if they regarded it as too little. They said: Who are we in comparison to the Prophet (peace and blessings of Allaah be upon him)? Allaah has forgiven his past and future sins. One of them said: As for me, I will pray all night forever. Another said: I shall fast all my life and never break my fast. Another said: I shall keep away from women and never get married. The Messenger of Allaah (peace and blessings of Allaah be upon him) came and said: “Are you the ones who said such and such? By Allaah, I am the one who fears Allaah the most among you and I am the most pious, but I fast and I break my fast, I pray and I sleep, and I marry women. Whoever turns away from my Sunnah is not of me.” Narrated by al-Bukhaari (5063) and Muslim (1401).  

Thus is it clear that no one has the right to forbid women (marriage) to himself. 

Thirdly: 

Whoever has done that has to repent to Allaah, may He be exalted, and he has to offer expiation for breaking an oath, because Allaah says (interpretation of the meaning): 

“O Prophet! Why do you forbid (for yourself) that which Allaah has allowed to you, seeking to please your wives? And Allaah is Oft‑Forgiving, Most Merciful.

2. Allaah has already ordained for you (O men) the absolution from your oaths”
[al-Tahreem 66:1-2]

Allaah has described the forbidding of something permissible as an oath. 

See: al-Sharh al-Mumti’ (10/475). 

The expiation for breaking an oath is to free a slave, or to feed ten poor persons with the average kind of food that he gives his own family, or to clothe them. Whoever cannot do that must fast for three days. 

This has been explained in detail in the answer to question no. 45676. 

Fourthly:  

The ruling on marriage varies from one person to another, according to financial and physical ability and how much a person needs to get married. In some cases it is obligatory and in others it is mustahabb or makrooh. See question no. 36486. 

And Allaah knows best.