He just ended our relationship as were about to do IVF

LondonGirl
I have been with my partner, well ex partner now, for 3.5 years. I'm 39, and he's 45, neither of us had children and had both been through divorces. We were excited to try for a child together; neither of us had ever really seriously considered or tried (to the point where in his previous relationship he had had a vasectomy!) but we said we had found each other and we wanted to have a child together.
He had a reversal last year and we had been trying for just over 12 months when we went to get tests done and found out that he was producing antibodies after the reversal that were killing the sperm. So ICSI was the answer. 
We were due to go on holiday in just two weeks (so that's cancelled too) and last night he dropped the bombshell that he was leaving as he had fallen out of love with me.
I'm in complete shock, devastated and in a complete state of anxiety now, knowing I am 40 in 4 months, having just lost the love of my life and now the possibility of having children closed to me. Although the tests showed my fertility is  good for my age, I can't face having a child alone, it was about being with a man that I love and us having this baby together. 
I'm devastated and don't know what to do, I don't know how to face work, or face anything. Just feel like sitting in a dark room and shutting everything out.
The heartbreak, the pain feels unbearable.
Any words of wisdom or advice would be really appreciated.