When her dc are threatened it can turn a timid and physically weak mother into a furious lioness who will fight off all comers in her desire to protect her cubs.
In this case, your dc by your previous relationship have had their lives made a misery by the father of your 3 month old yet you have lied to protect him.
In addition, this man has threatened to drown the child you created together and has also threatened to take the infant away from you, but you have failed to take any steps to protect your baby.
Isn't about time you got angry and roared said ENOUGH IS ENOUGH. I AM NOT GOING TO ALLOW YOU TO DO ANY MORE DAMAGE TO ME AND MINE. YOU ARE OUT OF OUR LIVES AS OF NOW - and mean it?
The house is in your name and he has no legal right to be in it if you don't want him to be. You can call the police anytime of the day and night and ask them to remove him - and there will be nothing he can do in law to get back in.
You can pack his stuff, stick it in the front garden, change the locks, and have the police remove him if he attempts to get into YOUR house.
In the time since you first posted, you could have taken yourself and your dc to the safety of a women's refuge where, if necessary, they would have helped you obtain an injunction and/or a restraining to keep this man away from you, your dc, and YOUR home.
But, apart from collecting up some paperwork and packing a small bag, you have done NOTHING to stop this man continuing to abuse you.
All that is going to happen on the 21st is that you are going to see another solicitor who will tell you what you were told by the one you saw some weeks ago.
There will be no magical solution unless and until YOU wave the wand that will make him disappear from your life.
You have friends who are willing to help you. You have family that you have neglected. You have a caring ex who deserves to know what his dc have gone through at the hands of a twisted, bullying, twunt. You have a source of internet support here.
You have the power to free yourself and your dc NOW. Please don't waste any more time. The law is on your side - use it.