SG0720, have you ever thought seriously about getting sperm from a sperm bank? You speak as if you're in control of you life and you know what you want and I'm just wondering, if you're anything like me, I want children, not 1 but at least 2 or more. I would do anything to have this including getting sperm to have my children if I needed to.
You could at least look into it, if it's possible, get to know the connections and get the referral/get put on the waitlist. When you OH lets you down next month, you could gently let him in on your plan. There's nothing like a little competition. It might put him into a crazy tail spin back to your bed!!! And if it doesn't phase him, try iui and have another child, your son would be so thankful to have a sibling to spend the rest of his life with. I think you'd be one happy girl for taking control of your life.
If you haven't already seen this movie, I highly recommend it even just for a laugh: https://www.imdb.com/title/tt1212436/