We are glad to come alongside you in prayer and counsel for your relationship. It is commendable that you are seeking God's will for your life and your relationship. Let us first address the arguing and lack of love for each other. This should not be the case and is not a good sign for a marriage.
First, remember the words of Paul in Ephesians 4:31-32 WEB: "Let all bitterness, wrath, anger, outcry, and slander, be put away from you, with all malice. And be kind to one another, tenderhearted, forgiving each other, just as God also in Christ forgave you."
Arguments and lack of love should be replaced with kindness, tenderheartedness, and forgiveness. This change comes from the Holy Spirit when we are in a right relationship with God.
Regarding your feelings of being unappreciated and unloved, consider the words of Jesus in Matthew 22:39 WEB: "You shall love your neighbor as yourself." And remember 1 Corinthians 13:4-5 WEB: Love is patient and is kind; love doesn't envy. Love doesn't brag, is not proud, doesn't behave itself inappropriately, doesn't seek its own way, is not provoked, takes no account of evil."
It is clear that both of you need to take steps to show love and appreciation for each other. True love is not just a feeling, but a commitment to put the other person's needs above our own. We must pray for you both to have this kind of love.
However, there is something here that is worth addressing that is a possible sin that needs to be "put away from you." This is the possibility of fornication. If you have been together for two years, possibly living together, and possibly engaging in any form of sexual activity, this must stop immediately. There should not be any form of sexual contact before or outside of marriage. Fornication is sexual immorality and is against the will of God.
1 Thessalonians 4:3-5 WEB: "For this is the will of God: your sanctification, that you abstain from sexual immorality, that each one of you know how to possess himself of his own vessel in sanctification and honor, not in the passion of lust, even as the Gentiles who don't know God."
We strongly advise you to repent of this sin if it is occurring, and commit to purity before marriage. You should be seeking a godly, virtuous marriage that honors God. Honoring God starts with obedience to His commandments.
Now, let us pray for your relationship:
Dear Heavenly Father,
We come before You today, lifting up this couple to You. We pray for healing in their relationship. Help them to put away all bitterness, wrath, anger, outcry, and slander, and replace it with kindness, tenderheartedness, and forgiveness. Help them to love each other as You have loved us, with patience, kindness, and a love that seeks the best for the other person.
We pray that You would help them to show love and appreciation for each other, not just in words, but in actions. We pray that You would help them to be of the same mind, maintaining the same love, united in spirit, intent on one purpose. Help them to do nothing out of selfish ambition or conceit, but in humility to consider each other as more important than themselves. Help them to look not only after their own interests, but also after the interests of each other.
We pray that You would guide them to a church where they can grow in their faith and be surrounded by a community of believers who will support and encourage them. Help them to be rooted and grounded in Your love, strengthened with power through Your Spirit in their inner being, so that Christ may dwell in their hearts through faith.
We pray that You would help them to keep themselves pure before marriage, and that You would guide them towards a godly, virtuous marriage that honors You. We pray that You would help them to be an example of Your love to the world, a love that is patient, kind, and never fails.
We pray all these things in Jesus' name. Amen.
We encourage you to continue praying for your relationship, and to seek God's will for your life together.
Prayer Focus: God, Thank You. Thank You for loving me. 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, mind, soul, body, 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. 
