If you are not sexually attracted to your partner, you probably need to end the relationship. Sex is an incredibly important part of any long-term relationship, and few things cause more problems than when partners do not fulfill each others' sexual needs. At best, one person ends up very sexually frustrated, and at worst it results in outright resentment and extramarital affairs. The only reason to remain in a relationship with someone you are not sexually attracted to is (1) they are not sexually attracted to you either and (2) sexuality is truly unimportant to both of you. If both of these criteria are met, it is theoretically possible to remain in a fulfilling relationship. However, this is extremely rare and tends to only happen when people have low sexual interest for biological reasons (such as age or disability). In addition, #2 is extremely hard to determine, because it is a difficult topic to have an honest conversation about. In any case, do not remain in the relationship unless you are willing to sit the other person down and tell them that you are not sexually attracted to them. If you are unwilling to have this conversation, regardless of the reason, you need to end it.