REPLY:  Thanks for writing. I think it would help to set this problem up openly, flushing it out openly, and then proactively getting in there to help the mare with this "buddy sour" (as it's called) problem. It's habit now in her and that habit needs to be broken into, to start showing her that it's not so bad to be alone for a little while, and show her what she can do instead of acting up about it. All horses do this, by the way, to some extent, just usually to a smaller, "less issue" degree. As herd, prey animals, the greatest fear of most all horses is: to be alone.

For example, we have 3 horses here that my husband and I own. If my husband and I take out two horses to play with, one always hangs at the pasture fence at first, watching. If we take off on the two, the left-behind third might whinny after us briefly, even follow the pasture fenceline until we are out of sight, but then they settle down and graze, waiting for our return. Horses are herd animals 100%. It's hard to be alone for them, but they learn the pattern (my buddy will return soon). I think your mare could use some help with that. You need two people for this exercise to help her with this issue now.

Have someone else remove the buddy horse out of pasture and then out of sight, and then step in and halter this buddy-sour horse. Bond with her (use this link on my site for bonding techniques to use there, paying closest attention to the finger in the mouth & dropping the head relaxation techniques you read there):

Horse Whispering "Tricks of the Trade" - To relax horse, build trust & bond them to us

Give her mind something else to think about, right there in pasture. Once she's settled down, is relaxed, just graze her on line there. Be there, but "be invisible" so to speak if/when she's relaxing more. You're stepping in and teaching her how to be without another horse in her pasture for a while. Step in and relax her manually if she tenses up or thinks about the other horse who is gone, but put her to work if she really acts up about it -- you're making the right thing easy, the wrong thing hard. Work on teaching her this if she's acting up and wanting to barge into you or trying to move your feet:

Leading Problems - Horse runs over human/How to teach horse back-up cue on ground

If she wants to move her own feet/run around, teach her this (which will keep you in the "director's chair" there):

Driving Horse in Circle Around You on the Ground

But as she's calming down, settling down, release the pressure and allow her to graze on line. Once she's grazed calmly for a bit, then (and only then) have the other person bring back the buddy horse and return it to pasture with this horse. Don't bring that horse back if/when your horse is acting up about the separation (work her as needed, relax her at those times); only bring the horse back in with her when she's relaxed/grazing. End the lesson there.

Couple days later (give the lesson a day or two to "soak"), repeat the exercise, but keep the buddy horse away for a little bit longer this time. Repeat the ground working/relaxing her in pasture, as long as it takes until she settles down and just listens to you, then relaxes. Then let her graze. Then you be invisible (no talking, no interacting, just "being there" in a way that will more duplicate her being alone in there). Each time you do this she should start repatterning her brain that she can be without the other horse for a while OR she will be put to harder work if she gets too acting-out about it. You're showing her manually how to relax. It takes as long as it takes. I hope you can follow me here. Be patient. Don't be too goal-focused about the problem, but be "in the moment." Over time, she's going to learn for the first time how to be without that other horse, and will listen to her "lead mare" (that would be you) that all is okay when the other horse is gone for a while. She'll learn: that other horse WILL be brought back and she survived just fine.

As for the bigger picture there, with you and your husband being new horse owners, you might think about getting my Whispering Way™ 12-Step Total Training System DVD set, because part of the problem there is this horse is not confident inside herself in general, and that's usually a reflection of training foundation holes that create the nonconfidence in the first place. The opposite of fear is: confidence. Confident horses aren't as insecure inside and out. The kinds of problems you're seeing there (including tensing up about the saddle, etc.) is simply about foundation training holes that you can plug up yourself (safely on the ground first), and that's what my program teaches. All the above and much more is taught visually and clearly in this DVD set. Plug both of your horses into the step by step program and not only will you be closing up all foundation holes (repeat: safely on the ground first), but also, in the process of applying what you learn there, your horses will better perceive you as their herd leader and be more willing to partner up with you when you come out to be with them. My program is designed to "do it yourself," and is even very beginner user friendly. You can read here a few of the many testimonials we have received from others who are following my program through my DVD's: http://www.naturalhorsetraining.com/ProductQuotes.html

I think that route would benefit you and your husband greatly right at this juncture. And it will speed along your natural horsemanship/horse ownership learning curve tremendously, with all the backup support you might need as you go along. My Complete Package, by the way, contains all the videos and "tools" you would need to apply my program.

One last link I wanted to direct you to on my web site -- to fast-forward your natural horsemanship learning curve in general -- My: What Is Natural Horsemanship? section.

I hope this helps and let me know if I can be of any further assistance to you. Happy to help any way I can!