I chose the wrong person who obviously didn't love me enough
Correction - someone who doesn't love himself enough. The sad clown loved me plenty - you should have seen all the love bombing! But it wasn't genuine not because I am not awesome (I so am) but because he does not love himself. He loathes himself, actually. The bandaid of new 'love' helps him loathe himself a little less. I was that bandaid for almost a decade. It doesn't work long term.
They don't cheat because there is something wrong with us. They cheat because there is something wrong with them.
Get the CS sorted ASAP. The longer you go without the easier it will be for him to claim you don't really need it. Read Shellybeanz recent thread - they will leave you high and dry if there is any way to do it legally.
The sad clown is incensed that he has to pay me a measly $8k per year out of his $250k income. I got the same bullshit story about how hard up he would be if he provided any more support than the CS calculator required him to (which caps at $120k).