Depressed & don't want to loose him

Hi,

I'm really struggling & feeling severely depressed.

My husbands leaving me for another woman & he says he's in love with her.

He told me his feelings are elsewhere two weeks ago & Its with someone he used to work with who I expressed concerns over at the time & has now reconnected with her & has been talking to her secretly for months.

Since finding out i have been incredibly depressed. Not wanting to leave the bed. Have not been sleeping or eating and have to force myself to get the kids ready in the morning.

I keep jumping from being really sad & depressed to moment's of anger at what he's done & what he is doing.

I've been trying over & over again to change his mind & convince him to pick me but he says his minds made up.

What this is doing is crushing me & I feel broken.

He says he's sorry, wants to remain best friends & that he'll always love me but I feel like he doesnt understand the pain and the betrayal I'm feeling or even the gravity of the situation.
I AM his wife, together 14 years & she is the other woman.
He should want to pick me. I should never have had to ask for him to pick me.
And Instead he's getting fustrated with me for not being ok with this already & can say really hurtful things about me, about them & about our relationship which makes me hurt more.

My mind also doesn't shut off. I'm having all these thoughts. Thoughts about not wanting to be without him.
Dreading him doing the things he does with me but doing them with her. Like I don't want him to kiss her! I don't want him to make love to her!
I know what he's doing is a mistake but what if they work out. What if he marries her. What if he gets her pregnant. These are all the things that would absolutely devastate me.

I'm also starting to have really negative thoughts about myself.
He's making me feel worthless, unattractive, that I'm less than. That he thinks she's the better option. I feel so unimportant, so replaceable. And I don't know if I want to be here anymore.

I keep asking Why doesn't he want me anymore..

I love him so much & I don't know how to change things.
I dont know how to stop the pain.