I found this article in the March 2018 Ensign. I hope it helps you understand better the whys of the temples.

The Blessings of Temples in My Life
By Elder Helmut D. Wondra
Area Seventy

My love for the temple goes back to my childhood when I knew it only from pictures and stories. Every time my parents came back from a visit to the Bern Temple in Switzerland, they always seemed happier and brighter than before--and they always brought back delicious Swiss chocolate. This way I gained a very positive connection to the house of the Lord at a very young age.
At the age of 13, I had the opportunity to see and enter a temple for the first time. Even just by looking at the exterior I was moved by the sanctity and purity of the temple. In the temple itself, I felt close to heaven. These feelings have only become deeper and clearer over the years.
Above the doors of the temple is written: “Holiness to the Lord, the House of the Lord.”
The Lord Jesus Christ is indeed the Lord of the temple. These holy houses are consecrated to Him and our Heavenly Father. Temples are sanctified by the presence of the Holy Ghost. Christ is the source of the power and the light emanating from the temple. All symbols and covenants, all ordinances of the temple, point to Him and His great Atonement and help us to become more like Him.

Our everyday life is often characterized by noise and turmoil. To leave it behind from time to time, to come to the house of the Lord and to open ourselves to an environment of peace and holiness brings peace to our soul.

In this pure environment it is easier for us to find answers to our deepest questions and concerns. In his first message as President of the Church, Russell M. Nelson promised the following:
“The ordinances of the temple and the covenants you make there are key to strengthening your life, your marriage and family, and your ability to resist the attacks of the adversary. Your worship in the temple and your service there for your ancestors will bless you with increased personal revelation and peace and will fortify your commitment to stay on the covenant path.”
The fulfillment of the great promises of the temple depends on how faithfully we keep the covenants of the temple and how much we actually consecrate ourselves to the Lord and His work.
We do not have to be perfect to go to the temple and to receive the wonderful blessings that await us there. But we should strive for the necessary worthiness and bring the sacrifice of a broken heart and a contrite spirit. For me, this means that I have to develop a malleable, soft heart--a heart that aligns with my Father in Heaven. A contrite spirit means to me that I adopt an honest attitude, that I am aware of my imperfections, and that I need the help of the Lord to return to my Father in Heaven.
The Lord has promised:

“Blessed are all they who do hunger and thirst after righteousness, for they shall be filled with the Holy Ghost.”

The greatest blessing I experienced in the house of the Lord was that I was able to lay the foundation of an eternal family together with my beloved wife. Because of the covenants of the temple and the sealing authority that is exercised there, we have the promise that our marriage will last for time and for all eternity, if we remain faithful to the covenants. We have the promise that, together with our loved ones, we may live forever in the presence of Jesus Christ and our Heavenly Father.
The fulfillment of this promise is worth every sacrifice.
Let us be a people that comes to the temple as often as possible to be sanctified and cleansed, to receive revelation and power from on high, to serve our ancestors and, through the covenants of the gospel and the grace of Christ, to receive all the blessings our Heavenly Father has in store for us.