Soulmates is a term that can be used to describe a relationship between two people who feel like they belong together. It’s not just for married couples, it can be used for any type of relationship between two people. Some say that their soulmate was made perfectly to match them. They are the only person in the world that they has this level of deep connection with.
--> You can refer to two people as lovebirds when they are obviously very much in love.
Jack and Mary are as happy as two lovebirds now.
--> 2人のことを lovebirds といえば、明らかに二人が[愛し合っている](https://eikaiwa.dmm.com/uknow/questions/51883/)という意味になります。
例
Jack and Mary are as happy as two lovebirds now.
ジャックとメアリーはおしどりのように[幸せそうだ](https://eikaiwa.dmm.com/uknow/questions/2845/)。
People who are married, and have been married for an extended period of time are quite often referred to as 'a happily married couple.' They may celebrate many milestones in their long time together such as their Golden Wedding Anniversary after 50 years of marriage. Jokingly, as with an old but reliable car, you may say that they have ' some miles on the clock.'
長い期間結婚されている人々はよく「a happy married couple」と言われています。
結婚の50周年としての金婚式のように、長く一緒にいたことを祝うことがあります。
冗談で、古いが信頼できる車と同じ様に「some miles on the clock.」と言うかもしれません。
After nearly 40 years together, they are still happily married!
A happily married couple ...refers to those who are " behaving like newly weds"
even after many years together! they are often called "Love Birds", "Soul Mates"
or simply "a perfect match"
幸せそうな夫婦は、何年経っても「新婚ほやほや」のようですよね。そんな夫婦のことを"Love Birds", "Soul Mates"
または "a perfect match"と言います。
To describe people who are happy in their marriage we use the term "Happily married"
For example: "We have been happily married for 10 years"
An idiom used to describe two people who are in a very happy and loving relationship we use the term "lovebirds"
For example: "Even though they have been married for 25 years, they are still like a pair of lovebirds."
仲の良い既婚カップルのことを
"Happily married"（仲睦まじい夫婦）
と呼びます。
【例】
"We have been happily married for 10 years"
（私達、結婚して10年仲睦まじくしています）
またイディオム表現で、とっても仲のいい関係のカップルのことを
"lovebirds"（おしどり夫婦）と言います。
【例】
"Even though they have been married for 25 years, they are still like a pair of lovebirsds."
（彼らは結婚して25年にもなるけど、いまだにおしどり夫婦のようです）
The term "lovebirds" is commonly used in the U.S. It is the perfect way to describe a couple that is very happy and in love. Lovebirds is used to describe a young couple or a couple that is older but still love each other as if they were young and have recently fell in love.
We also say they are madly in love.
lovebirds（仲のいい恋人同士、おしどり夫婦）は、米国ではよく使われます。とても幸せで仲がいい夫婦、または恋人（同士）と言う時に良い表現です。
lovebirdsは、若い恋人同士、または老夫婦について使われますが、若かった時のまま最近好きになったように互いにまだ愛し合ってます。
they are madly in love（お互いに猛烈に恋してます）とも言います。
A couple who are absolutely devoted to each other.
An inseparable married couple
To emphasize the love and care between a couple, they can be described as being "devoted" to each other. This means to be very loving and loyal to one another,
A married couple that is very much in love can also be described as "inseparable". This implies that nothing can separate or break them apart, they are as one in their love.
アメリカ合衆国 
南アフリカ 
イギリス 
