You say that you aren't willing to lose one or both of these women.Since you are unwilling to choose, my first question is why can't havetwo girlfriends? Are you receiving pressure from one or both of thesewomen to make a choice? Are you leading a double life and lying to themboth?
If the latter is true, then peace of mind will be impossible foryou to find. While it is true that humans are capable of loving manypeople, having two romantic partners is leading you down a path thatwill end in disaster. Most women don't take kindly to sharing theirpartners with someone else. Sooner or later, you are going to lose atleast one if not both of these women.
It is always possible that youare seeing two women who have the same unfinished childhood business.For example, if these two women had a parent who wasn't available tothem; perhaps a parent who cheated on the other, then they wouldnaturally choose a guy like you who recreates their childhood trauma.In that case, you would be perfect for both of these women. I highlydoubt that both of these women are playing out their childhoods withyou. More likely they are either unaware of what's going on or waitingfor you to choose.
I remember an old psychoanalyst who told me about apatient who spent years obsessing over what career to choose. He wasequally drawn to two options. After decades, the analyst finally said,'It's time to shit or get off the pot.' The same applies to you. Youcan't have your cake and eat it too (unless you are dating two of themost unusual women I've ever known. I've never met a woman who likes toshare her boyfriend. I highly doubt these two women are comfortablesharing you!)
Life is about choices. Each choice is the elimination ofother choices. The fact that you won't choose tells me that you mayhave been over-indulged as a child and given whatever you wanted whenyou wanted it. If this is true, then you never learned to befrustrated. You learned that you could have your cake and eat it too!This over-indulgence would predispose you to giving yourself whateveryou feel like having, including a relationship with two differentwomen.
It is also possible that your refusal to choose may cover a deepfear of commitment and intimacy, which itself covers a deeper fear ofabandonment and/or rejection. Until you give your heart to one person,you aren't loving anyone fully.
Now I know that religious servantsdon't marry or give themselves to any one person, so that they are freeto do their ministry and love everyone. But, you're not a priest!You're a lay man--no pun intended! So, since you don't live in apolygamous society, you are going to have to make a choice or become aMormon!