This is one of those times when the best course of action is to switch off the emotional half of your brain and to think about things in a purely logical way for 1 hour.
Resolve that you are going to think like a Terminator robot for 1 hour.
Looking at your life logically:
You were fighting and arguing a lot - so it's no huge loss that you've broken up, as at least you'll have more calm and less stress in your life now.
The him being busy with work thing was just a feeble excuse on his part. The 2 of you should have lived together full time. As man and wife. And then you'd have seen plenty of each other and would have shared in chores and therefore been more time efficient as a partnership.
Most important logical thought of all - do you live in Sark or somewhere like that or do you live somewhere where there are plenty of men about? If you live in a poulated area, there will be thousands of men you can meet. And so the loss of one man is neither here nor there in the grand scheme of things.
In other words, logically thinking, are you in a situation of abundance or one of scarcity?
Self imposed scarcity doesn't count. Because with logical determination you can overcome any self imposed restrictions.
There are a few lessons you can learn
Making up stuff to test someone is dumb. Life throws up enough tests as it is. For example every time the 2 of you argued was a test.
Sunken cost fallacy. It's so human to fall into this. Be aware of it and try not to fall into it.
No man is worth getting upset over for more than 2 days. After that pick yourself and get on with getting your next sexual partner.
Just because a relationship ends, doesn't mean to say there's anything fundamentally wrong with you.
You got a boyfriend before. You can get one again.
Thinking about things logically should put you in a better mood.
Because logically you are in a great place now and there's a lot of reasons for expecting that great things will happen in your future.