If I lock my STBX out of the house tonight

[NotSuchASmugMarriedNow]

what can he do about it?

[sunshineandbooks]

Depends on what your justification for it is and how far you are prepared to go.

I remember some of your previous posts and I remember that your STBX has treated you very badly indeed. I cannot remember if you have actually been physically assaulted by your STBX (sorry).

I'm not an expert on the law, so please don't take my word for this and do some checking out yourself, but I think he has every right to force entry into the marital home (assuming it is in both your names) unless you can demonstrate you have good reason to feel that your safety is at risk. You can go to court and get an emergency injunction to keep him away if you need to go that far.

However, even with no legal safeguards in place, if he turns up, finds he's locked out and starts shouting, all you have to do is call the police and they will insist he leaves.

[NotSuchASmugMarriedNow]

thanks for that, so if he tries to break in the house or even starts shouting, i will call the police is that the right thing to do

[LaurieFairyCake]

Do you both own the house ?

If so he can just break in (though the police may stop him or tell you to let him in) but he cannot assault you obviously.

If it's both yours why don't you go somewhere else?

[2rebecca]

STBX? Sexually transmitted bionic xylophone?

[Anniegetyourgun]

Soon-to-be-ex. (I'm not sure, but I think I may have been the first to coin that, around 4 years ago.)

[BertieBotts]

You need to be careful though. My friend locked her P out of the house one night because he was being drunk and abusive, she phoned the police and they told her she had to let him in, even though she was afraid he was going to hit her

They CAN arrest him though if he is causing a scene because it's technically a breach of the peace.

[BertieBotts]

and I don't know why they didn't in my friend's case.

[SpringchickenGoldBrass]

If his name is on the lease/mortgage and you don't have an injunction in place to keep him out then legally he can break in. However, if he then behaves aggressively, you can call 999 and have him forcibly removed by the police.
If the house is in your name, you can lock him out, though.