Thanks for the replies, guys!
SchrodingersCat & suadade
L knows about my relationship status being open. I've talked with her at length about it on several occasions. It was interesting hearing her response, as I sensed a lot of cognitive dissonance in her words -- on one hand she really likes the honesty aspect of polyamory; on the other, she couldn't seem to wrap her mind around it. She said, "People can connect and be good friends without having to 'go there.'" By that, she meant sex and physical intimacy. She is a very flirtatious person by nature and thrives off of that part of herself. Unfortunately, H doesn't like that and tells her so often, as do other people in her life who see it as a "problem," and so she has guilt about it and tries to minimize it.
Recently L called one of her exes when H was away and had a wonderful reconnection and felt a pull towards this other man. H was not happy about this and their therapist agreed that it was emotional cheating. More and more she feels this guilt about who she is -- according to the common culture, she is a love addict or attention seeker. I simply perceive her as someone who is very open and loving. My partner and I are thinking about giving her The Ethical Slut
to read; maybe this will offer her another way to look at herself. Most people, as many of you here know, don't realize they have the polyamory option in relationship.
As for H, to be honest, I hesitate to mention polyamory around him. He is far less open than L is in terms of talking openly about relationships, let alone polyamorous ones! Maybe one approach is to ask L if she has talked to H about the idea of this at all. If he seemed receptive to it, then maybe we could move forward. For some reason, I don't see that happening due to H's insecurity in relationship. And you guys are right: depressed and isolating folks like H need love and companionship, too. On the other hand, L shouldn't have to dim her candle just to appease his moods -- that would be codependency.
It's funny because I've actually considered just going for it without disclosure. Not the most honest option in the world, but it might be the only one that would work in some way. I have feeling that, if things don't get out in the open soon, L and I might find ourselves alone and, well, you know where that can go ...
Thanks all for the advice. For now, I think I'm going to ask L about whether or not she has talked with H about polyamory. Trying to be patient and take it sloooowww ...