I can only answer briefly, but, you are 30 years old, give or take a year or two? So Mary is in her early 20’s? A woman in her early 20’s really doesn’t have all the R tools needed. A guy with a S4 and going through a divorce is something that a woman that young isn’t equipped to handle. You said she was inexperienced at relationship. So her first real R is a relationship she wasn’t equipped to handle as an adult. And that does not define how lovable or unlovable you are.
What would be important is to explore why you find no happiness in your life unless you are with someone else or in a pretend gaming land. I think the gaming is great as it is your hobby. Is there anything else that you take interest in? Why don’t you look for local groups that support single dads and find some friends there. There is a lot of value in life with your son and yourself and you should be enjoying it regardless of you have a partner or not. Start digging deep as to why you are so attracted to that immediate love connection. I mean, pretty much everyone we chose to date gives us that feeling initially. Then sh!t gets real. I think you might surrender yourself to that feeling a little too hard.
I spent many years without a partner raising a very young child. I got lonely at times. Then it became more often than not. But before that, I took some good years enjoying my life with my daughter, my friends, with my own hobbies. I wanted nothing to do with relationships.
Go find yourself. Because yourself is not in someone else