How should I approach talking to my husband about this?

Tell him what you need. Communicate to him how important this is for you, that it matters to you, that you need him to be brave for you and the babies.

I would avoid doing anything that smacks of trying to guilt him into doing anything, though. "You'd do this if you really loved me," or that sort of thing. It sounds like your husband has a bit of a fragile ego.

The best way to approach it, then, I think, would be to appeal to that ego by making him feel needed and wanted.

It's kind of dick thing for him to do, though. He really should be doing whatever you need without, you know, having to be asked.