We are truly sorry to hear about the pain and disappointment you've experienced, ###. It's important to remember that God has a plan and purpose for your life, and He will bring the right person into your life according to His perfect timing. In the Bible we are warned against being unequally yoked and that if two are walking together and they are not in agreement then one is walking with the devil. Be thankful for the past not working out and having the engagement broken. Be careful to avoid premarital sex as this gives away your purity and will almost always guarantee a poor marriage outcome.
Firstly, we want to address the fact that your previous engagement was with a man who was already married. This is a grave sin in God's eyes, as it involves adultery. God clearly commands us, "You shall not commit adultery" (Exodus 20:14 WEB). It is also mentioned in Exodus 20:3, Do not have any other gods before me. (this is a warning against being unequally yoked) It is wonderful that you have broken off this engagement, and we pray that God will continue to give you the strength to wait for the spouse He has prepared for you and a Christian believer.
We will pray that God will open the doors for your marriage, in His timing and according to His will only if you are obedient and following His laws and Commandments. Remember, "Delight yourself also in Yahweh, and he will give you the desires of your heart." (Psalm 37:4 WEB). It is important that your first delight is in your relationship with God, as Jesus said in Matthew 6:33 "But seek first God's Kingdom, and his righteousness; and all these things will be given to you as well."
We also lift up your parents' health to the Lord, praying that He will strengthen and heal them. "For I will restore health to you, and I will heal you of your wounds, says Yahweh" (Jeremiah 30:17 WEB).
In all of this, remember to cast your burdens upon the Lord, for He cares for you from 1 Peter 5:7. "Cast all your anxieties on him, because he cares for you." We must never forget that God is the ultimate healer, provider, and the one who will guide us to the perfect spouse. We are praying you will seek God's will and follow Him more closely.
Let's pray together:
Dear Heavenly Father,
We come before You, lifting up our sister ###. Lord, we pray that You will heal her heart from past hurts and that from this day and forever she will seek you and only you for direction.
Help her to wait patiently for Your perfect timing regarding her marriage. We pray that You will open the right doors and bring the godly spouse into her life according to Your will. We also pray for her parents' health, that You will strengthen and heal them, especially her father's ### and her mother's ###.
In Jesus Christ we have access to You and You have made us righteous and holy in Your Presence. We pray for boldness to preach this message of the gospel of the kingdom to all who come in our path. We ask that You will encourage her to be a light for Christ and an example of Your love and faithfulness.
Finally, we pray that you will convict her of any hidden or known sin that she may need to repent of and become righteous and holy in your Presence. In Jesus' name we pray. Amen.
Prayer Focus: God, Thank You. Thank You. Thank You. God Thank You for loving me. Thank You for loving me, Jesus. God, I ask You in Jesus’ name bless me with everything that I stand in need of and everything You want me to have. Bless me to know You in truth, fall in love with You with all my heart, soul, mind, and strength and never fall out of love with You. Bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, and Your righteousness. Help and strengthen me God to always respect and obey You. Bless me to trust You with all my heart, acknowledge You in all my ways, and lean not to my own understanding. 
