With your family cuento, it is easy to see why you cannot go straight away getting hold/control of your life.
But the sad thing is, sis, your mom is running that way coz she loves you. Unfortunately, her love for you may be colored by selfishness (she seems to want you tied to her apron strings forever), lack of discernment (hindi nya ma gets you need total support now vs that monster in-law family & flawed husband), and pre-occupation with her/the family's public image.
You are an intelligent and brave woman, sis. You exhaust all means first to honor your life commitments (husband, in-laws, your mom) before making hard but necessary decisions. Keep it up, your son will love you more for being such.
BUT there is that tricky Life Element: Timing. Time things right, and most chips fall in place for you... Time it wrong, and events/noble intentions/the best-laid plans go boink! Hopia.

So, I would say: there is always a Best Time for shooting someone...I am kidding, but I sure mean it figuratively.
For now -- step back, breathe. Your grrrrrs are warranted, but it is best to think out plans with a clear mind.
You are just too focused now on people who dealt and continue to deal you bad cards. You need to override their power to color your world. It is easier to modify your perspective than to make people realize what gad-awfool human beings they are.
When I was at my wits' end, and I had run out of options, plus I was bone-tired of life.... What got me going positively, or kept me from shooting myself and a couple other people (ano, swerte nyo? Aba! Hindi ako mag-iisa. Lol) was when I just told God: "No more deals from me, God. They Will be done, let the chips fall where you want.".... Then I also prayed to the Holy Spirit to " give me clarity of mind
to be abe to think things through clearly, and the courage to act.".
We may not share the same religion, KIKAYGIMIKERA, but there is great value in tapping for help/discernment the Higher Energy of The Universe.
Am I saying you just pray, and wait? Heck, no; God helps those who help themselves.
It will all come to you --- how to work things out given your unique circumstances and strenghts, with proper timing.
In the eantime, breathe and let things and people be.
In the meantime, it may be helpful to vent and discuss with a competent and non-judgmental stranger; who will show you new/better communication ways to use with the people who create grrrrrs in your life. (PM )
File for Child Support -- it is your son's legal perk. Then get your marriage annulled -- coz no doors should be closed to you.
Sure, appreciate it that people can accept you unconditionally even if you are afflicted with the condition: Married. But that does not mean you will diminish your perception of your self-worth. Sis, you are worthy of unconditional acceptance and love because of your good heart, persistence and strength of character.
You just need to sort out one grrrrrrrr at a time; and learn to choose which grrrrrrr deserves your attention, or deserve none at all. Do not let the many little grrrrsssssss nor bad things set in history to defeat you. Hello?!
So there, breathe, step back. Think clearly, but do not over think. It will all come to you, just trust yourself. So, Sis, do not doubt yourself, just because there are so many grrrrr things in your life now. Just continue to do what you deem is right, given the circumstances -- and do not be distracted by people's negativities. Hwag mo akuhin mga kasalanan nila.
Breathe, step back. Take care of yourself.