@ThankYouMama you are in denial. You are hugely damaging your children. You are so wrapped up in yourself and your partner you seem to have little thought for the impact of any of this on them at all.
How could leaving a 17 month old with a severely mentally ill man all day long, who you cannot bear to be around and who has behaved abusively to you, be appropriate? Do you think this is good parenting?
Then you send the baby off to live with someone else because you think it would be hard for you to manage him and a 6 year old, who is at school most of the day?
The poor baby has lost his primary care giver - such as they were - and now been taken away from the rest of his family and his home, has no way to understand what is happening. You are going to cause him HUGE issues. Why are you doing this? Because you'd rather go out for lunch with your friend?
You say you don't want him around you all day but would have if he was a girl. So messed up.
You didn't want to take your 6 year old to school and let him have some normality because you feel anxious. You might have a panic attack taking him in but apparently are fine to go out to lunch with friends or toy shopping in busy central London.
Your 6 year old will also not understand why his brother has vanished and may well think you'll dump him off next.
What sort of parenting is this? What kind of stability? Get some intensive therapy for yourself set up, stop navel gazing about yourself and start putting your children first. Get them both home, give them a routine, put them first and behave like a parent. And hire a nanny to help you if you need to. Their father isn't capable of being a decent parent so YOU need to step up and do it. Prioritise them, not yourself and him.
Honestly, it's just horrific to read and so utterly selfish. Those poor boys.