When a shy courier, in a bad marriage, is allured by the friendly wife of a drug criminal, he pursues her help to overcome his social anxiety, despite exposure to his wife's brother by police phone taps.

Way too much plot for a logline. Hard to keep track of who’s who to whom, or doing what, or why?simplify. Try to do it without any commas at all, or just one if necessary; MAYBE two but that’s usually avoidable. Even some of those you used aren’t necessary, without even changing or cutting out any words.

Here’s a possibility:

“A shy courier in a bad marriage gets involved with the wife of a drug dealer his cop brother-in-law is investigating.”

In this form you don’t even have to specify what the protagonist “must” do because the conflict is already clear.

So what’s at stake? He has to risk something or there’s no tension. In my example, the unstated yet clearly conveyed stakes are his own life — if the dealer catches them he’s probably dead, and if the cop catches him he’ll be in jail as an accessory. In your shorter version, what happens if he doesn’t overcome his anxiety? Nothing. Nothing changes. No stakes.