Separated, divorce started. Ex-partner not allowing me to hold keys to home

As per subject. We have been separated for 6 weeks and upon moving out my ex partner made all sorts of threats if I kept a key to the house.

I was fine with this initially to try to keep the peace, but she is going away with the children and the house will be empty. During this time I am starting a tenancy in a new flat. I have asked her to give me the key before she leaves, so I can move my belongings into the flat without having to make contact. She has refused, saying she is 'not comfortable' with this arrangement, and has insisted to make me wait until she returns. This will mean that she and the children will be in the house when I am moving items out, and I don't want them to be there while this is happening.

what are my rights (I believe I am within my rights to have a key to the house) and is it possible to enforce this quickly and easily? My tenancy starts on the 14th August, so approximately 1 month away

You use the term “partner”, are you married.
Who owns the house and who currently covers all the costs for it?
What threats did your ex make and what have you done about it?

Thanks for the reply. Sorry I left out some important details oops.
Married for 17y, three kids under 18
Separated since early Jun, divorce applied by me, she accepted early Jul

Not sure if correct term is still wife or ex wife, soon to be ex wife or what so I went with ex-partner lol

Her threats were mainly along the lines of making my life difficult with accusations of domestic abuse

House is jointly owned by the two of us. I am sole earner paying for everything. She chooses not to work, has own business, not yet profitable

If it’s the marital home you have the right to live in it.

Ok that’s good information. So in this case is it reasonable for me to expect her to need to give me permission to enter the home when she is not there, or to unreasonably withhold permission? I simply want to collect my belongings so that I can move in to my new flat on the day I collect the keys, since I will have been sleeping on a portable mattress on the floor for nearly three months by that time. For her to make me wait until she returns from holiday so that she can be involved seems unnecessarily awkward, bordering on controlling or power-tripping!

What you want doesn’t sound unreasonable to me.