Confusing sex issues

We started off very active, then he had changes in his home life that caused him to be depressed. He's not very sexually active with me anymore. We talk about his erectile dysfunction, but my issue is not just that, but the loss of passion and effort to affection. No more making out, no more pleasing me. We used to do threesomes, he thinks if we try it again maybe it will spark something. I feel like he's just using it as a Bandaid solution, but I can tell his issues is more deeply rooted. But I'm willing to temporarily treat the symptoms if it helps without pushing him too much and making him feel bad about his ED. I've suggested other treatments and he agrees to them, but his depression gets in the way from accomplishing them. Also part of me is paranoid about there being someone else in the picture. Although I used to be ok doing threesomes, I feel less comfy doing it cuz our one on one sex life isn't great. It's almost like i need to be comfy and confident in our own sex life before involving others.