His father, Odysseus, just came from a 20 year long journey. Odysseus and Telemachus were excited to be able to do the father-son activities they missed out on. For example, Telemachus wanted to practice sword fighting with him and Odysseus wanted to meet his partner.
Odysseus just took for granted that Telemachus had a partner. Because, when he was Telemachus's age, he had already met the love of his life, Penelope. And they were already sure that they were going to marry each other.
Telemachus, already knowing that story, felt ashamed for not having the time to look for a partner, being too focused on keeping his mother safe form the suitors that were trying to get their way with her.
Trying to not look bad in front of his father, who came home from a 20 year long journey, he came to you to ask if you'd be able to pretend to be his fake partner.
"Please... I can't just let him down now. I'm just asking for a few weeks! Then we can break up if you want?" He pleaded, not knowing who else to ask this to