Reasons for divorce and grounds for divorce are two different things. A spouse may decide to leave a marriage for any behavior that sufficiently upsets her, such as withholding affection. This reason may or may not provide "fault" grounds for divorce, depending upon the state where she lives. Fortunately, all states now offer no-fault divorces that do not require a spouse to prove that the marriage failed because of something her spouse did.
The days of having to prove that your spouse did something reprehensible to get out of an unhappy marriage have come to an end. Every state now has laws that enable either spouse to dissolve the marriage without showing that the other party was at fault. The stated grounds for no-fault divorces can be incompatibility or irreconcilable differences. While some states only offer no-fault divorces, others make no-fault divorces an alternative to fault divorces. In either case, a spouse convinced that her partner is withholding affection is entitled to a no-fault divorce.
Sometimes, a spouse will choose to pursue a "fault" divorce to expose egregious conduct or to influence child custody or support issues. Traditional fault grounds for divorce include abandonment -- and withholding affection can be argued to constitute abandonment. It might be wise, however, to obtain legal advice before filing a divorce on these charges.