Partner has erectile dysfunction around time of ovulation

The first 2 months were fine. I was using a calendar & tracking my most fertile dates but wasn’t really telling him when I was ovulating just kind of trying to do it every day or 2 days. But obviously didn’t get pregnant. So since August he has been struggling with erectile dysfunction. We argued today as on my ovulation app it said I was ovulating today. so I tried last night to get him in the mood & he said he was tired from work & football (we’d did it the night before) and he said he wanted an early night. So in the morning at the sound of my first alarm I cuddled up close to him and started kissing him (initiating sex.) which it did start to happen, but I moved to a different position and I’m literally seconds he lost his erection (not the first time it’s happened since we’ve been TTC) and I’m so frustrated because now I feel like I’ve missed my most fertile times now. He tried to get it back again but I just got up because it just frustrated me. 

He said the pressure of doing it knowing I’m fertile is too distracting and it makes him loose his erection. He doesn’t want for it to happen but he can’t help but think about it. 

It shouldn’t be like that. I even tried again with him tonight as it says I’m ovulating Today & he’s brushed me off said let’s start fresh next month. So I’m really upset and annoyed now I have to wait another month. I mean there’s been other times we’ve done it that’s possible for me to conceive and we can Of course keep trying even if my app says I’m not fertile it can’t hurt. But I’m so frustrated and upset that this month hasn’t been used to it’s full potential. 

Has anyone Else had similar problem an how did you deal with it ??