Stress can definitely make you tired and want to sleep all the time. Don't forget to take care of yourself in the middle of all this. Eat well, exercise if you can, and treat yourself well.
You can love someone and still not deal well with each other in a relationship. The boyfriend may be great, but, if you are prone to loving others in addition to him, he may never be able to handle it. The choice you end up with is either he changes for you, or you change for him.....and I suppose some one somewhere may have made that work, I have never had long term success with trying to change for someone.
You may end up with neither of these guys. You may end up starting over. Starting over is not the end of the world, though it does seem scary sometimes. You are used to depending on your boyfriend for stability, but, I have to advise you that your own two feet are far more stable than depending on anyone else. Work on becoming independent. Work on loving yourself and figuring out what you really want.
When you are happy with your own self it is far easier to find partners who are good for you. (my experience. I'm 43.) When you are really ready to go looking for poly folk, OkCupid is one place that I have had good results. Get the deal breakers out and visible and find the people who consider all your quirks pluses rather than problems that need to be fixed or polished away.