First, Ares was the son of Zeus and Hera and therefore was Aphrodite's half brother. As the god of war, he fought on both sides in the Trojan War, wherever he could stir things up more. (Aesculapius was not his son but Apollo's.)
Are you perhaps thinking of Aeneas, who WAS Aphrodite's son? His father was Anchises, a member of a different branch of the Trojan royal family, and there are faint hints that there's some friction between Aeneas and the sons of Priam in the Iliad. Neverthless, Aeneas fought gallantly in the war and even had the courage to face Achilles when Achilles returned to battle. That incident is a good illustration of one aspect of the Greek concept of fate, because Poseidon, who sides with the Achaeans, nevertheless whisks Aeneas away from Achilles because he knows that Aeneas is fated to survive the war--and that any warrior who faces Achilles is bound to die.
The Romans claimed Aeneas as their ancestor and had a tradition that, after the Trojan War, he led a group of survivors to Italy. He's the hero of Vergil's Aeneid, which foresees that he will marry an Italian princess, Lavinia, and that their descendants will build Rome.
As for Helen, after Paris was killed, she married his brother Deiphobus, who was killed during the sack of Troy. (In the Aeneid, Deiphobus' shade in the Underworld tells Aeneas that Helen hid his sword and then let the Achaeans into the house.) Euripides' tragedy The Trojan Women (written more than 300 years after the Iliad) depicts Helen's meeting with Menelaus after the war. When he enters, he is determined to kill her and is undecided only as to whether to do it then and there or to take her back to Sparta to make an example of her. At the end of the act he decides on the latter alternative, and viewers in Euripides' time would already have been familiar with the Odyssey, which shows her restored to her place as Queen of Sparta, with maids to pamper her and Menelaus dotingly wrapped around her little finger.
If you mean the god ares, Hera and Athena guided the hand of the Achaens to strike ares, and in pain he went back to Mt. Olympus. His son Ascalaphus was killed he wanted to join the Achaens and fight against the Trojans, but Athena convinced him not to. When Zeus declared the gods could again aid the war, Ares fought Athena to avenge his injury and his son but she overpowered him via a suprise attack with a boulder and he went back to Olympus.
but btw, if that is the ares your talking about then he's not Aphrodite's son, he's her lover who she persuaded to fight with the Trojans in the first place
Helen loved Paris only b/c of Aphrodite's spell, so when Paris died, it was broken and she returned to Sparta and lived out the rest of her days.