There are limited grounds for obtaining an annulment under English Law and one of these is non-consummation of the marriage.

However if you have had sexual intercourse with your partner at least once since you married then the marriage has been consummated and you can't use this ground.

There are other options such as one party having a venereal disease at the time of the marriage and the other party not being aware of this, one party being pregnant with a third party’s child at the time of the marriage and the other party not being aware of this or one party not giving valid consent to a marriage because such consent was given under duress.

All grounds for annulment use fairly unusual circumstances and it may be better to consider a divorce.