Yep that’s the line alright. If you’re going to keep it all about the physical sex you need to do just that. You can’t have long conversations and get all hot and steamy all day long. If you’re spending hours connecting with the new guy and not with your husband it’s no wonder your connection is shifting. It matches your attention. Now there isn’t much wrong with having that emotional connection as long as your husband is ok with it. That is the difference between swinging and polyamory. Have you shared all this with your husband yet? Not doing so crosses the line between Polyamory and cheating. Maybe your husbands reaction will surprise you. Maybe he will step up his game at home or maybe he’ll be really happy for you.
I’ve always found that exclusion is the best way isolate someone. Lol Isolated lovers don’t stay that way for long (stay lovers that is). Best bet is to talk with him tell him how much you need him and this guy while nice is a poor replacement for the man you love. Let him know you understand that he can’t do what you both really want/need because of his injury but you’d like him to be involved some how. What ever way he’s comfortable with. Maybe he will want to know all the details or want to take pictures of it. By integrating him in a way you’re all comfortable with and having open communication you can foster a healthy new reality where you satisfy your needs and express love and respect for your ailing husband.
Hope that helps.