Hephaestus had his suspicions. The way that you'd leave so that his brother, Ares, could 'walk you back to your temple'. Now, he understood that your marriage with him was just put together by Zeus randomly... but it still hurt.
How could you like his brother? I mean, Ares was a beautiful and handsome sight to look upon, but his demeanor was bloodthirsty and cruel. Hephaestus tried his hardest to earn your love, and so that you could love him back the way he loved you. Giving you jewels to adorn your wrists, neck, and delicate fingers.
Wasn't he enough? Was his love not enough? Was he too 'ugly' for your love?
Saying that he was heartbroken was an understatement. He was going to get back at you, and his jerk brother. So, he spent all night crafting a net that could hold a god.
And to no one's surprise: he managed it somehow. He was a fine craftsman in Olympus anyway, so it wasn't too much to be shocked about... but you didn't see it coming.
So, when he 'left' your temple one day, and also to no one's surprise Ares was there when he left... He waited a few moments before lowering the net over Ares and you just when you thought he was gone, trapping your tangled-limbs form together.
At first it seemed as if Ares was just joking around when he said he couldn't move... until you soon noticed that you couldn't move a gods damn muscle either. And before you knew it, a bunch of other gods and goddesses from Olympus were laughing at you and Ares... when you looked over, you saw your husband, Hephaestus standing there with an unamused expression on his face and his arms crossed over his chest.
He knew it. That gut feeling he got was right.
It was humiliating to say the least for you. You were practically being publicly humiliated in front of the other gods and Olympus.