She sounds like she is not functional for marriage or any sort of Christian relating. The Bible says,
"Therefore submit to God. Resist the devil and he will flee from you." (James 4:7)
So, our Father does want us to personally submit to Him, then all the time be submissive to Him, with our attention always to Him. So, this thing with her could be a trick to keep your attention tied up elsewhere!
And our Apostle Paul says . . . for how we are to relate with one another who are children of God >
"submitting to one another in the fear of God." (Ephesians 5:21)
To me, this means we are to be mutually submissive, not one lording oneself over the other. And this is "in the fear of God" > if we are in fear of God, aren't we being attentive to Him? And so our relating is with our attention to God and prayerfully submitting, all the time, to how He has us sharing with one another.
So, our attention is not only to how to handle one person, but how we are relating with each and every other Christian . . . while learning also how to relate with unbelievers. So, it is wise not to get yourself isolated only or mainly with what to do with these two women, but share with much more mature Christians . . . including ones who mentor any pastors who might talk with you. We need our senior Christians; so make sure you listen to whatsoever they say; and I would say not to first or only bring attention to your problems with these two women. But first talk about being with God.
"Listen to the Holy Spirit, and do what He tells you to do."
"God can turn things around."
God does desire for us to love and care for even any evil person, at all, with hope for every unbeliever, like how Jesus on the cross so suffered and died with hope for any evil person, at all.
So, you should not only be concerned about evaluating her, but have hope for her. But do not accept being only subject to her. But also do not try to control her, but >
"nor as being lords over those entrusted to you, but being examples to the flock." (1 Peter 5:3)
Be ready to share in a good way, not to argue or complain or get bitter or try to judge and accuse her and make her accountable to you. But be her example, and she is welcome to join you, but she is not going to steer you. If you stay humble and gentle and "without complaining and disputing" (Philippians 2:14-16), you will see if she relates with you and stays with you, or not >
"swift to hear, slow to speak, slow to wrath" (in James 1:19).
Possibly, if she claims she wants to be with you, you can say, well good, then, you will want to share with all my Jesus family people . . . at church and our prayer and Bible meetings where I am going, so you can grow and learn with all of us as family. Marriage in Jesus is not isolation with only some one person. Is the other lady isolating with you???? If you are in God's love with someone, I will offer how God's love is all-loving > "For if you love those who love you, what reward have you?" (in Matthew 5:46) There are people who make love idols . . . only certain people they want to use; and in our idol loving we are not in the strength of God's almighty and all-loving love; and so we can break down in weakness and suffer various personality torments . . . because of seeking what we want from our love idols!! and staying weak in the process.
Now, one might say, how do I know I am really submitting to God in His own peace (Colossians 3:15, Philippians 4:6-7) and how He has us sharing and relating? Well, God knows. If you try to bring me to task about how to make sure, you could be distracting yourself from actually doing this with God Himself. So, only God is able to correct us . . . how He does this >
Hebrews 12:4-11.
So, it could be so simple > if you are in the dark and not sure and you are only or mainly discussing and arguing ideas and generalities . . . you need more real correction which only God can do. And He is the One who will make you sure; so if you aren't, trust Him to correct you, deeply, in your nature, so you are reliable with Him. And do not accept any less; keep praying and seeking Him for Himself.
We can not make our own selves experts at submitting to and obeying God. It is how He first changes us so we are truly submissive to Him and trusting Him. Our nature . . . our character . . . needs correction so we succeed. Of our own character we are not so good and honest and humble, that we really mean it when we say we want to do God's will. Peter did that, boasting how he would go through anything with Jesus, then to discover how he did not exactly.
So, if we are really with God, we know it and it shows. If we aren't, then we still need more character correction so we are submissive and in His light which has us seeing right and clearly. If you are still not sure, then I consider that you and I both need to do the same thing > get however God corrects us. We are not smart or honest enough . . . now . . . to know the difference, like we could if we grow more in God's love with His light to make us clear. We need what God is able to do, so then we will be clear.
So, we all are in this together; don't let yourself be tricked into thinking you're all on your own and the only one who can be unsure and unclear. But stay gentle and humble with her, and talking about being honest and praying for what God wants, not only trying to negotiate with her about what she wants. And then see if she wants you

. . . while you with your Jesus family all together are seeking God and His will . . . not isolating yourself with some one person and problem!!
About these people who are telling you to marry the new lady . . . how mature are these people? Have they been helping you to first get real with God so you can know His will, even at every moment, in His peace? > Colossians 3:15 < Being ruled by God in His peace is all the time, with time out for correction, "of course", I would say. So, if these people are so reliable, why haven't they already ministered for you to be able to sense and do God's will, all the time . . . versus going on and on in conflict and discussing????
Are you sharing with senior and very mature married Christian couples and others much more mature?
I don't mean nice talkers and smiley-face people.
I suspect you have not been staying with senior and very mature Christians who I think would have already ministered you into knowing what you are doing. And I don't know how much maturity you have in your present church situation. But doing God's will is not only about knowing how to make things happen. People can learn and be trained in how to administrate without truly growing in Jesus. If we submit to Jesus, "you will find rest for your souls," He guarantees, in Matthew 11:28-30.
So, whatever you have found in 1 Corinthians chapter 7 is meant to do with all else which is in God's word, and this in sharing with all the mature Christian people our Father shares with you.