hmmm I'm not sure how helpful I can be by telling my own personal experience but mine happens to be the opposite.
I have all the soul connection at the 5th dimension (none of them are really materializing in this 3D world but surely if I look at any members of my soul group on the photos/videos/any works they've done I can see how we've been always together and working for the same purpose/at the same institutions (if not at school...). The disparities in 3D world with them don't mean anything at 5D) and when my connection with TF got strong gradually enough to the point where he's the only one matching me as the opposite sex, well, I was cut off from all the connection to my soulmates (they are all guys for whatever reason; quite a few of them enjoy the romance with me but the majority of them are just like my dear bros) at 5D.
Soo I didn't really have to do anything to have any of the relationships "right"...I didn't force myself to prioritize my TF nor trying to see less of my SM for any particular concerns, such as clinging to the "ultimate prize" that is TF... (in fact, I think I did the opposite; trying to escape from my "fate") but it's naturally happened.
I did think of the possibility this morning that he was doing this out of jealousy or simply due to the desire to control me but Naaahhh. I won't even question it because I've never experienced any negative energies at 5D and jealousy is one of them. I don't experience any "power/influence/force" at 5D either so he's not controlling me at 5D. The unconditional love that rules there that is It's entirely different from the romance we experience as "playing games" which obviously involves cheating you mention as one of its tactics.
According to my own experiences, you are not indulging romance with TF. So I'm not even sure if praying that your TF gets her own lover she deserves is something she needs/even asks. If I were her, I would say to you it's none of your business lol.
Love (unconditional one) is simply there for acceptance, not for your self-esteem. If you are not just ready, it'd be smart to not act like you are already ascended (from this 3D world) or something. You'll be guided by following your heart and intuition anyway.
So why don't you let go of the concept of TF/SM for once so that you can see what/how you are more clearly by just not trying to obey the social norm (anything that comes from the outside you)? Most of the time, any soulmate connection is here to bring us the blessings to remind you of your true self, and I assume that's what you're experiencing here now.