1st wedding anniversary

Next month, we`re my fiancé and I are going to celebrate our first wedding anniversary.

Be more specific.  The reader does not know who "we" are.
Now I am thinking how and where we should spend it togethers...

Here, the added word "should" shows that you want to know what is the best thing to do or place to go to.

"Should" also sometimes shows what would be the "right" things to do.

Little Boy: What should I do today?

Little Boy's Brother: Let's go to the park and place baseball.

Mother: No, you both should clean your room.

Little Boy: いやだ、掃除したくない！

Should I write a letter to him? Should I watch movie with him? Should we have a great dinner at the a restaurant?
Should I give him some a gift?
Anyway, I am going to thank him with all of my heart.
Could you pls let me know if you are me how to spend with your partner on the anniversary?

Could you please let me know how you spend your wedding anniversary with your spouse?

"Spouse" is a special kind of partner.  A spouse is your husband if you are a woman, and your wife if you are a man.

＃ 結婚記念日はどうでしたか？何しましたか？家族と幸せは同じですね。

1st wedding anniversary

Next month, we`re going to celebrate our/the 1st wedding anniversary.
Now I am thinking about how and where should we spend it together...
write a letter to him? watch movie? have big dinner at the restaurant?
give some gifts?
Anyway, I am going to thank him with all of my heart.

Could you pls let me know if you are me how to spend with your partner
on the anniversary?

Congratulations on you two~I prefer to spend my anniversary on travelling.^^