Re: "Am I selfish or unreasonable"
Ask her on a date. Yes, she has a lot of things to worry about, and so do you. But I think to keep your relationship going ( I assume you're not divorced and are trying to work it out? ), you both should put some work into getting intimate again. Where did you first meet or have your first date? Go there if you can, or emulate it the best you can, and just have a few hours alone. Talk with her and be honest about how you feel, including the jealousy, how you feel as a man, everything. Let her know that you still desire her. Even if she doesn't feel like she wants sex right now, that may change later on if you start "dating" again. If you can and you both want to, just start out all over again with kissing, cuddling, holding hands, and later on you could get to fool around. ( If it gets that far again, I would definitely make it fun like when you were young, doing things you're "not supposed to do" in places you might get caught, things like that ).
I think that she has just accepted that things are tough, and so sex got put on a back burner. Find out if she still wants you and is attracted to you, and be romantic or goofy or whatever you did to attract her in the first place. Give her compliments, cards, flowers if she likes them, thank her for everything she does and most importantly - tell her that you love her, every day. Let her know that you're still attracted to her. I don't think she's dried up down there, she just needs a little sweetness and romance to get her going. Give her a kiss every day if you can, and maybe that will lead to a squeeze or more later on. If you're adventurous enough, you could send her some cheeky texts, just make 100% sure you have the right number before you send it!
This is going to be a long process, don't forget that. Don't ever force anything on her, and don't get angry or upset if she says no. That shows her respect, and she will respect you for it. I wish you all the best, and hope that your family all gets through the tough times.