OP I wrote a long post talking about how your situation mirrored my own life and giving advice and somehow it disappeared, even though comments tend to stay around. So I'm just going to be brief now.
All your feelings of disappointment, resentment, hurt etc are valid. Don't be gaslighted into thinking differently.
In the past you were young, naive about the emotional spend a relationship (especially with kids) takes. Naive in uncoupling financial security from love and commitment. They are absolutely tied together, which I think you see now. Because you were young you concentrated on the wedding. Now with maturity you realise it's chiefly about the value of the marriage and the deeper values and insurance it symbolises.
Your partner does not.
So, do not. DO NOT waste more time hanging on, hoping for a change. You are 38, but it flies fast and before you know it you are 48 approaching 50. Your partner does not appreciate you and all you have contributed towards his happiness and the happiness of the family the way he should do. You are not appreciated. Your feelings of rejection, resentment and insecurity will grow as you age if you keep the status quo.
Start slowly gaining your own independence. I'm not saying leave now, that would be unrealistic, but start detaching your dependency and start getting angry about the way he is undermining you.
Gather your strength in the background. In addition to the excellent advice here, it's crucial that you go out and get an outside hobby. Something. Meet people or socialise with friends more and when men approach you whilst out and about talk to them (I am not suggesting you swap numbers or anything, just engage in friendly convo). Start getting your confidence up. How is your self care? Treat yourself to new make up and a few new fashion items. Go to the gym or swim, or jog. Do it for yourself. You need to nurture yourself.
Also, this is crucial: DO NOT ASK HIM TO CONSIDER MARRIAGE AGAIN
Nothing signals desperate, can't live without you, and you are the prize, than a woman begging a man to commit (as unfair as the situation is)It will actually shift the dynamics and cause him to withdraw even further away at a faster rate. You need to be signalling that YOU can pick and choose if you want. The man has forgotten who you are.
Look at single mum accounts for inspo. I like this one here
https://www.instagram.com/reel/DHttYo5uGZu