My second child is the worst sleeper ever

For those who read my blog, I'm fairly certain it's not news that we now have two children. I don't think anybody reads this thing who doesn't know me in real life, certainly not now that I've been absent from blogging for about a year and two months. But, just in case you didn't know, L is now 2 and a half, and her little brother, J, is coming up on 5 months old. L wasn't a great sleeper, she woke up 2-3 times a night until she was 9 months old or so, and then at least once a night until she was about a year. That being said, from the time she was 5 WEEKS old, I would swaddle her, nurse her, and then put her in her crib in her room where she slept for the entire night. I'd stumble across the house in the middle of the night, feed her, and put her back into her bed. And I thought that was less than ideal. But then, she started being a super sleeper, going to bed easily at 8:30 when she'd sing herself to sleep and sleeping until 6. She is still that cheery little sleeper. Cut to my life now- I have a son who has insistently coslept since day 1, nursing constantly throughout the night when he was newborn *and I do mean constantly* until he was around 2.5 months old, when it switched to nursing every 2 hours but still wanting to be in my bed because that's where he was comfortable. He never liked being swaddled as L did, never would stay asleep after being put down, as L did, and truthfully, I didn't have the energy to fight it in the early months like I would have with L. And so now, here we are, with an almost 5 month old who is incapable of sleeping alone. As I write this, it is night 4 of attempting sleep training, and he has been screaming in his crib for almost two straight hours (with us going in to soothe at intervals). Things are, in fact, getting worse, as the first couple of nights he settled down after an hour or so, and slept in his crib for an hour before waking up for me to retrieve him (at which point I just brought him to bed with me like the weakling I am). I sought help from some breastfeeding resource groups in our area early on, and was immediately vilified for being "unwilling to just do what the baby clearly needed" and continue cosleeping. I let them shame me into continuing what I knew wasn't sustainable. I hear that cosleeping wotks for some people- I am not one of them. "You'll look back on this time and just be glad that you were able to cuddle with him every night" "If he's crying it's because he has a legitimate need to be held and soothed" "You're doing emotional damage by letting him cry at all" .... these were some of the kinder comments my requests for help solicited on a facebook group. One person actually begged me to let him cosleep because she had been orphaned at 18 months and couldn't bear the thought of any other child crying for their parents like she knew she must have... dramatic. I knew better then to let him stay in my bed, but I didn't do better. I guess this is my word of warning to anybody out there reading this who might be about to have a baby- first, second, seventh, whatever- unless you can see yourself sharing a bed with this child until he's ready to head out the door to middle school (where teasing should take care of him still wanting to sleep with Mommy and Daddy) don't put the kid in your bed. Don't don't don't don't. Sleep on the couch with them if you must. Insist on swaddling even if they don't seem to care for it. But don't put them in a bed that you share with them or they will fight gum and nail to stay there. Unless you need a kick in your pants to start your blog back up while waiting for them to go to sleep (SERIOUSLY KID????)