Defendant first assigns error to the refusal of the trial judge to submit the tendered issue of condonation to the jury. *59Plaintiff contends that there is no error because condonation was neither raised in the pleadings nor tried by implied consent under G.S. 1A-1, Rule 15(b). While it is true that the pleadings contain no allegation of condonation by plaintiff of defendant’s alleged adultery, we do not think this precludes defendant from litigating the issue. G.S. 1A-1, Rule 7 (a) provides in pertinent part, “There shall be a complaint and an answer; a reply to a counterclaim denominated as such; . . . No other pleading shall be allowed except that the court may order a reply to an answer or a third-party answer.” In the first action husband pleaded adultery in his answer but made no claim for affirmative relief; wife was not entitled to file a reply. In the second action, husband pleaded adultery in his reply to wife’s original answer wherein she had asserted a counterclaim; again she was not entitled to file any further pleading. G.S. 1A-1, Rule 8(d) provides in pertinent part that “Averments in a pleading to which no responsive pleading is required or permitted shall be taken as denied or avoided.” Under Rule 8(d) plaintiff-husband’s allegations of adultery were deemed denied. A party who is not permitted to file a responsive pleading may meet the allegations at trial in any manner that would have been proper had a reply been allowed. Vernon v. Crist, 291 N.C. 646, 231 S.E. 2d 591 (1977). Given this construction of Rules 7(a) and 8(d), we need not consider whether the issue was tried by implied consent under Rule 15(b). We conclude that defendant-wife was entitled to present evidence of condonation, and accordingly we now consider whether there was sufficient evidence to submit the issue of condonation to the jury.

In the present case the defendant pled abandonment as a ground for alimony without divorce and as a defense to plaintiff’s claim for divorce on the ground of one year’s separation. Abandonment requires that the separation be done wilfully and without just cause or provocation. Overby v. Overby, 272 N.C. 636, 158 S.E. 2d 799 (1968). Adultery is adequate cause for separation. Caddell v. Caddell, 236 N.C. 686, 73 S.E. 2d 923 (1953); Williams v. Williams, 230 N.C. 660, 55 S.E. 2d 195 (1949); G.S. 50-5(1). In the present case the evidence of con-donation was introduced for the purpose of establishing that adulterous acts by defendant did not provide cause for plaintiff to abandon defendant. Condonation is the forgiveness of a marital offense constituting a ground for divorce. 1 Lee, N. C. Family Law, § 87 (1963). Adultery is a ground for divorce. *60G.S. 50-5(1). “Condonation is forgiveness upon condition, and the condition is, that the party forgiven will abstain from like offense afterwards, and moreover treat the forgiving party, in all respects, with conjugal kindness; and, if the condition shall be violated, then the original offense shall be revived.” Lassiter v. Lassiter, 92 N.C. 129, 136 (1885). Voluntary sexual intercourse by the innocent spouse, with knowledge or reason to know that the other has committed adultery, usually operates as a condonation of the offense. Sparks v. Sparks, 94 N.C. 527 (1886); 1 Lee, supra, § 87.

The evidence, when viewed most favorably to the defendant, tended to show that from January 1972 to November 1973 the plaintiff suspected that his wife was committing adultery; that they had sexual intercourse on at least one occasion during that period; that defendant never denied her husband sexual relations; and that the last time they had sexual intercourse was in August 1973. We conclude that this evidence is sufficient to raise the issue of whether plaintiff condoned acts of adultery committed through August 1973. We are not unmindful that plaintiff’s evidence tended to show that defendant continued to commit adultery through November 1973, and that condonation is conditional upon cessation of the marital misconduct. However, in this case the jury was not limited to finding adulterous conduct after the time that defendant’s evidence tended to show condonation. ,If the jury had found that the only time that adultery was committed was prior to the time defendant’s evidence tended to show condonation, as would have been sufficient under the instructions given by the trial judge, then defendant was prejudiced by the failure of the court to submit the issue of condonation and she is entitled to a new trial.

Defendant’s remaining assignment of error pertains to the charge on adultery. We think that it is unnecessary to discuss this assignment since the error, if any, may not be repeated at the new trial.

Judgment vacated and cause remanded for a new trial.