Hi there! I am hoping to help you problem solve here this evening... it sounds like an extremely frustrating situation, no doubt... and you say you have continually asked him to stop interrupting you by taking calls, etc?
I am wondering if you have also simply walked away when he ignores you, and what his response is to this?
This is my thought: you are an intelligent, motivated woman who has temporarily lost her power. Your career was a powerful one, and you temporarily shelved it to be a mom... and you feel powerless in your relationship, and probably as you say, a bit less than yourself as a "shell of a person". What we need to do here is take the focus off of him for a minute and shine a light on you... finding ways for you to get some power back in some way.
His behavior is disrespectful... and you can no longer allow yourself to be a victim of disrespect.
First, there needs to be a firm boundary put in place; you have to somehow lay down your concerns and state that you will no longer tolerate this disrespect. When he turns away, you will, as well. You will immediately call someone who loves you and chat... or go online and connect with a friend... or go out for a walk... or go to bed and read... the reaction has to be somewhat immediate and different, and a kind of a shock to him. Don't talk... he isn't responding to this. Act... withdraw... do something comforting for yourself as a response.
Send the message non-verbally... you will have to of course tell him once that you are un-plugging from this relationship unless he takes you seriously.
Second, you need to gain some power otherwise... are you taking good care of your body right now? With little ones, I know this is challenging... but are you a runner, or walker, etc...?
Don't worry.... you will. But, if you do all the work, it leaves nothing for him to do to take the relationship, and you, seriously. He has to face the fact that you are serious about expecting some respect. Although you are smart enough to know that you can't ever put your eggs totally in anyone else's basket, and you have to take ownership of your own feelings of insecurity or powerlessness, you still deserve to be treated as a valuable asset, and as his friend. He wouldn't treat a friend this way, and you are not just an expendable piece of paper... and he may have to discover this through a temporary disconnect in order to be made aware of your value to him.
While in a disconnected period of time, you have to maybe just focus on you and the kids. I know it sounds a little intense, or scary, but it is temporary... it is "you" time.
And, I am glad to hear that you joined the gym, etc... this gives you power, physically and emotionally...
Trust me; sometimes when we talk to our partners without acting, they see us as filled with idle threats. It takes action to make a point, for them to take us seriously... he sounds like as you said, a kind and nice enough man, but limits to behavior must be enforced! I know you can do it!! :-)
My pleasure! Let me know how it goes! This chat will remain in your "my questions" tab to access it again at any point, and find your power, girl!! :-)