Yellow... let me address the training first.
Yes, you ran 14 miles today and felt bad. You know why too. Heat, especially if you haven't been running in it... can be a killer. It's been beating me down for months. My performance has suffered. It happens. Don't let it get into your head.
As far as the longer distances... and thinking about them... if you haven't done them before, it can be scary. When I started running 8-10-12 miles for training sessions... just thinking about it, I was scared. Could I do it? Would I be able to make it? What if...??? All you can do is go out there and try it. Right? If you make it great, if not... then that's OK too.
You really have to decide if running those distances and training for this race is going to make you happy. It's hard for some people to run the longer distances... I know for me it is. When I think of running 10-12 miles I get kind of... blah about it. The thought of running for 2.5 hours does not excite me much. It's mentally and physically hard. Do you like the mental and physical challenge? Or is it miserable for you?
Ok, so outside of the training you have your husband who is NOT supportive. That's a really hard one. Especially with the longer distances coming up. It's going to be hard to run 20 miles and not have it affect your home life. Unless you can get up and run before he wakes up.
Is this race and training for it worth the arguements and the unhappy husband? Being married... well, it's a compromise... 50/50... and if he's not going to accept your training for this race that is something serious to think about. With that said... this the very reason why I'll never be married again- ever. I'm not made for marriage... because I would tell him to screw off and deal with... no wonder I'm divorced... eh?
I wish you the best of luck in your decision.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"