Trying my hardest

My husband and I have been TTC for 5 months now. It's both our second marriage. I have 2 children from previous marriage and he has none of his own. He really wants to have a child I the worst way. There's nothing I want more than to give home that gift. The problem is for the past 3 months we have been missing that one day to get pregnant. He seems to not be able to perform on those crucial days. Any other day the sexy is wonderful except the days we need to do it. So yesterday was our day. He owns his own company and I work with him everyday. He's extremely busy during the day which I totally understand but when we finally got the opportunity, his friend showed up to play cards. Of course I got upset when I got home from work to find that his friend was there. My husband did ask him to leave but after he left we argued for a little and made up. We had Sex but he just couldn't cum. I know we weren't in the right dram of mind but we have been trying for so long and every time he can't cum. Then when I get my period he gets all upset and sad and tells me that I'm timing it wrong and I need to let him know so he can save up his sperm. He makes me feel as if I'm not getting pregnant is my fault but in all reality he's the one not able to preform or is too busy to do it. I know he wants this baby I just think he thinks about it to much and becomes under pressure. But times running out my biological clock is ticking. Please if anyone has any onsite on how I can get him to perform when he needs to please help!