i bet after all is well and malec got back together, alec will literally have the phobia of ever keeping anything, no matter how menial, from magnus..
Magnus casually walking into Alec’s office,
Magnus: Hi sweetie~
Alec *paused in his mid-morning discussion with Jace, Clary and Izzy to smile and kissed his boyfriend*: Hi. What are you doing here?
Magnus: Oh, i had some work nearby here and decided to stop by. Btw, here you go Blondie~
Jace *caught a small pot of cream thrown to him*: What’s this?
Magnus *’innocently’*: Oh, Alec told me about that nasty rash on your tushie-
Jace *spluttered*: What! Alec, that was supposed to be a secret!
Magnus: - and so i thought i could be a nice guy and give you some ointment. That’ll be five rubies, please~
Jace: The fuc-!
Magnus: Oh and here’s some for you too, biscuit. I figure you might need some too coz of Jace. Yours f.o.c of course~ It wasn’t your fault your boy is… well, him~
Robert: Alec, what i’m about to tell you is highly confidential and you can’t even tell Jace.. The Clave wouldn… Alec, are you listening? What are you doing?
Alec: Hmm? What? Oh go on. don’t worry, I’m listening. I’m just texting Magnus. Could you speak a bit slower so I could type them all exactly?.. Hmm… Maybe I should just call Magnus and put in him on speaker~ What do you think, dad?
Magnus: *stares at Luke*
Luke:… Uh, Magnus? You okay? Is there something wrong?
Magnus: tsk.. tsk.. tsk.. i thought i know you *shaking his head disapprovingly*
Luke*looks at Alec*: What’s wrong with him?
Alec *uneasy*: Uh..
Magnus: Maryse.. really~?
Luke *yelped*: You told him~? I thought we told you not to tell anyone.. Maryse doesn’t want this to go out yet
Alec: And I didn’t tell anyone~I just told Magnus.
Magnus *oblivious, still keep going on*: - Omg, does this means you are my future step father-in-law?? Do I have to call you Dad?? This is a tragedy, Lucian! How could you get it on with my boyfriend’s mother~?
*A small portal appeared and suddenly Magnus’s head pokes in*
Magnus *looks around*: Where’s my boyf.. Ah, Alexander darling~ don’t forget to come home early tonight, okay~.. Cat and Raphael would be coming around 8 and we’ll portal to Morocco from here. See you later,sweetie. Love you~
Alec *goofy grin*: Love you too~
*Magnus popped out in shower of glitter*
Imogen *in strangled voice*: This was supposed to be a secret meeting in a secret place which no one.. absolutely no one except those invited, should know about.. let alone a Downworlder! What do you have to say for yourself, Mr Lightwood?.. Hello, Mr Lightwood..? Are you even listening??
Alec: *still sporting goofy grin thinking of his bae’s beautiful face*
Robert: *look above with a ‘why me’ face*