Regular here with a namechange, for obvious reasons....
I've been with my partner for a couple of years. We live together, I have 2 dc, and he has 2 dc that stay with us for half of the week.
We love each other very much, that is never in doubt.
But just lately, there are issues with erectile dysfunction. This happened the first night we ever slept together, and I know that it was nerves, soon righted itself, and it's been mostly ok ever since.
But every now and again, it rears it's ugly head. Or not! 
So I don't dripfeed, we're having somewhat of a crisis at the moment. Nothing major, but I've made it clear that I cannot and will not carry on putting up with his exw interfering in our lives to the degree that she does. It's a massively long story, if I were to go into it, but suffice to say, she calls/texts him 6 or 7 times a day, interferes with our time with the dc, changes the rota constantly, arranges things for the dc to do when we have them, and will NOT bend on any of it. It's a nightmare, to be honest, and it needs sorting, or it's going to kill our relationship stone dead.
When we're in bed together, everything is fine. He gets an erection, until I touch him, and then he loses it. He gets really frustrated to the point of anger (with himself), and I really don't know how to help him. This doesn't happen all the time, maybe once a month? The rest of the time, everything is perfectly fine.
The reason I'm posting today is because it happened again last night, after we had had The Talk about how I'm feeling within our relationship. And I think the two things might be connected.
I really want to work through this together, I don't want him to think I'm going to do one just because of this problem, his confidence is getting more and more shot by the day, so it's a vicious circle.
Does anyone have any advice? How do we get through this? I hate seeing him so upset, but I can't physically help him at all. I've never experienced this before with anyone. He promises me that he finds me attractive, swears blind that he wants me.... but why is this happening?
Am not ignoring any replies, am at work, promise I'll keep an eye on the thread, even if I have to wait until tonight.