Depressed and stressed to the max

Recently I found out my SO had been looking for a prostitute and it hurt really bad... In all honesty it's put so much more stress on this cycle. He was diagnosed with multiple myeloma so the chemo is both for(keeping him with me)and against(killing his sperm count) us. I've been so anxious these last 6 months and so tired for the last 4 since we started ttc. With every negative test I feel like more and more of a failure to him... if I can't even do this for him what use am i?