Goodness, you need someone to look out for you.
Can one of your parentss or a sibling or good friend come over to help out, and explain if it’s brought up, that this isn’t satisfactory behaviour.
You can travel as much as you did before, to see your family. Your partner and his child can go too if they want to ?
But don’t let them stop you from getting out and about if you want to.
You need your family at this time, quite often.
Lock your bathroom door ! No one comes in the bathroom when I am in the bath, ever.
If you have no lock,and no one to fix it, take a chair upstairs, tip it over and jam under the door handle, or jam towels under the door so it can’t be opened easily ( youngest learnt how to undo the lock from the outside and let themselves in 😀)
You could mention your situation to a midwife or health visitor, but I’m reluctant to confide much in these people, just keep it to baby stuff for them.
If your partner is this unreasonable at the moment, is he normally like this ?