I'm running a campaign of D&D 5e with a few friends of mine, all of us being first timers in the genre. We play online, since some of us live too spread-out to meet regularly.
We are about to hit our first-year anniversary for the campaign in 1 or 2 months.
But since the beginning we had trouble with one of the players. To give a quick rundown of the situation: he eats up almost all of my attention as a DM, mainly by simply talking every one else down. Whenever I speak for an NPC or ask the group what they want to do or whatever, as long as it is directed at the whole group, he jumps in and talks... and talks... and talks. And whenever someone else says something, even just a small, "Hey, we could do that...", he goes right to "I WASN'T FINISHED".
At the start, I thought I could deal with it; I simply stepped in and said as the DM "Hey, person A over here has something to say too." It seemed to work at first, but slowly he started to get more and more upset about these incidents, not that I cared a lot since I thought, "He'll calm down, whatever, I'm playing with more than 1 person here."
But this backfired, as I realized recently; due to him getting upset and literally depressive for being shut down (after 5-10 min of him speaking non-stop mind you), the other players seem to take pity on him and now don't even try to add anything when he's talking. This leads to everyone shutting up for 90% of the game, i.e. his "screentime"... One player already quit over this, and I keep getting complaints from the others since the campaign gets boring for them... even though no-one would speak up against him during the session.
So right now I'm out of ideas on what to do.
I don't want to kick him, since me kicking him would, I fear, lead to even more pity for him (he's damn good at crying), but I feel like everyone is too polite to help me deal with this in any confrontational manner.
I even specifically call out other players for what they think/want to do when he's at a good point to finish his talking, just to have them say (in an annoyed tone), "Just let him finish first (eyerolls so hard you can hear it over the Skype call)". (They seem to be annoyed at him, not me, as far as I can read into it.) I'm actually not sure if he ignores those cues or if he's not noticing them.
I would appreciate any guidance you all can provide on how to resolve this problem, based on your own experiences.
Is my group just too nice/spineless? Am I just bad at GMing? What can I do to involve everyone again?