MyI didn't answer wasn'tvery quickly.

However, I decided to suggest that my husbandwe visit the theatere.

just writing "my husband" makes it sound that he will go without you. Also, as your language is set to british english, i corrected the spelling of "theatre".

We will go to the theater on May 5 ¶
the fifth of May. I hope that our date will be very nice and pleasant.

fifth of May is the more standard way to say dates in British English. You don't need to say both nice and pleasant. If you want to, you shouldn't use "very" with pleasant: "I hope that our date will be nice and pleasant."

However, I decided to suggest that my husband visit the theatere.

Pasha was very happy to hear this because he loves the theatere.

We will go to the theatere on May 5 the 5th of May.¶
I hope that our date will be very nice and pleasant.

UK dates. Always the day first and then the month. Everyone understands month then day, but it just sounds wrong.

However, I decided to suggest that my husbandwe visit the theater.

“My husband” sounds like your husband will go to the theatre alone!

We will go to the theater on May 5 th. ¶
I hope that our date will be very nice and pleasant.

These should be two sentences. Also, use “th”, “nd”, “rd”, or “st” after dates (e.g. January 1st, May 2nd, August 18th etc.)

However, I decided to suggest that my husband visits the theater.

Naturally, we would say 'visits' here: he visits, she visits, etc.

We will go to the theater on May 5 .¶
I hope that our date will be very nice and pleasant.