We've been married for 4 years, have small children. Nothing can get done around the house unless she feels the time is "right". She never wants to discuss house projects unless she's feeling up to it, but if I start them without her, she throws a fit. We never go anywhere, because it's "too much effort".

I'm being made to feel like the entire relationship is solely about her feelings, and I hate that. She makes me feel like I am the cause of all the problems, but then doesn't want to discuss it. My feelings don't matter to her, because apparently if I discuss my feelings with her, they hurt her. If I don't discuss my feelings with her, then I'm hurting her.

I'm at my wit's end, she wasn't like this when we were married.

How many children do you have and how old are they? Caring for young children can become overwhelming. She may also be suffering from some type of depression. You may want to try couples counseling ; it sounds like both of you could benefit from that,

Go buy the book Five Love Languages by Gary Chapman. It will help you understand your partner and why is she acting this way.This book discusses the issues in marriage. If you can't find this book, get back to me and I will just share to you what I've read and learned. I will be honored to be of help to you if it means saving your marriage from a complete disaster. God bless

Does she work ? Do you share household duties, cooking, dishes, laundry? How old are the two of you ?
What type of projects are you talking about, and what type of going out are you talking about ?

Good questions that others have asked that were not mentioned---all play a big factor in the root of the problem...
What are the ages of the children?
What age range are you & your wife?
Does your wife work? Do you help her with household duties?
I think she could be overwhelmed , or maybe even depressed. You both should seek counseling

We never go anywhere, because it's "too much effort".

That statement caught my attention. Like others said, she may be feeling depressed and/or anxious. Counseling may be in order.

In the mean time, surprise her with a bouquet. ;)