Long story short, my confidence is all a shambles after a pretty bad wreck (wasnt even riding, just wrong place at the wrong time, horse I've had for 12 years booted me in the face as she blew past me). And now I have 2 coming 4 year olds with bucketes of brains and talent and struggle to make myself do anything with them. 

Before the wreck, I rode all kinds of horses, mostly unbroke horses with quirks, issues or just plain green. Just the last few years I started getting a couple of my personal horses to the point where they wre honest and trusty to go use, or make a run on (ones a 1-2D barrel horse, the other is my ranch horse). So, I bought two prospects. 

Both of those colts are perfect angels, and have been wonderful for their first 5-10 rides we put on them over the summer before turning them out. Thankfully, I was able to talk my fiance into helping me get them rode (read: he rode them when I made him, I only put 3 rides on the more forgiving filly), but being their 3yo year I had wanted to get a number of outside rides on them and be at least working on loping some circles etc. We accomplished 1 ride outside of the roundpen with the one filly, and the other was pretty much abandoned all fall. My fiance isn't around for or interested in helping me all the time, and if it were 4 years ago, I'd have no problems working these horses by myself, but now I just feel like I cant ride well enough, I'm not feely enough, I'm going to ruin them.... it goes on and on. And it's just these young colts that are the problem, I've been riding a green Hancock mare this year and my confidence to ride her has been just fine. 

Has anyone had to overcome this? What did you do to help? Do I just bite the bullet and send them off for 30-60 days this winter or spring so I can feel better about riding them by myself? 

I lost confidence. I had a bad wreck and then didn't ride for 5 or 6 years. Since I'm 61 now, I've lost all my strength and muscle tone and I can't move as fast as I used to. I even have a hard time cleaning out a foot. I also struggled with going out there and doing anything with my horses. I bought a new horse that I thought would be more suitable for me. He's little. Technically a pony. And very quiet. BUT it turned out he's also very green. (I didn't catch that because he's so quiet.) I've trained my own horses. I trained my 3 old guys. Got them when they were two-years-old with 30 days at most under their belts. I even used to give lessons to older riders and people who were fearful. But the first time I rode the pony at home, the saddle started slipping and I got scared. My husband encouraged me to get some help because he saw I wasn't having fun. I hired a young trainer girl to come over twice a week and ride him. It's the best thing I have ever done. Already I have more confidence because SHE is doing the training and at the same time, I am getting to know him. Things like, now I know he's not going to buck if the saddle slips.

In your case, you're okay with the Hancock mare. So you don't have a general loss of confidence. But these colts, you really don't know what they are going to do because colts can be unpredictable. You should get help with them like I did. When you know they are okay, YOU will be able to continue their training. 

There are a couple girls that specialize in building your confidence back up when you lose it with your horse. They have a good following and I plan on taking a course this spring. One Felicity Davies and the other is Jane Pike. You find them on their websites and on Instagram where you can learn a little about their programs and how they think. 

Same issue here. I'm older and have some physical problems that affect my balance and my ability to know exactly where my hands and feet are. I have 0 confidence in my riding and I have 3 young horses. Got Donene Taylor's book today. I hope it helps. I'm also working out at a gym. 
Edit: I am utilizing a professional trainer. I can't do it alone.