I do understand I just think it's really two different issues perhaps.
How he handles his meetings, support etc is really on his side of the street. So if it's a distraction that concerns him, he should look at that, if you know what I mean. A person's sobriety is really up to them, only they know what is a good support and what isn't.
As for the issue of the him spending 3 hours a week in meetings with his ex, personally? I would just ask him. Ask him why he has chosen to attend a meeting with his ex who he knows is pining after him. I know that ex's can be friends in some cases, but that's obviously not the case with her? Have you discussed the issue with him at all?
Have you checked out Al-Anon? They also have online meetings now and you might find them really helpful. Lots of support for you here as well, of course.