Solo fertility treatments for no 4?

Have recently split up with my boyfriend of 15 years as he was cheating. Right before I found out we were thinking of going for a fourth and final baby. I'm 38 and would absolutely love one last baby, time is ticking by away. Would I be crazy to do solo fertility treatments? I was basically a single parent before as I paid for everything to do with the children and did all the baby/child care. I also have a big family that's always willing to help if I need it. I feel like my ex will kick up a fuss though