Married to vs married + for as a duration

[dwni1]

For instance, I want to express how long two people have been married.
1 Are both sentences okay?
1 He has been married for ten years.
2 He has been married to his wife for ten years.

Does it depend on whether the verb is followed by a preposition when we use for as duration?

 

[Tarheel]

Both sentences are fine. Unfortunately, I'm having trouble understanding the second question. However, you seem to understand the form. (See below.)

Bob: How long has he been doing it?
Ned: Ten minutes.
Bob: How long can he do it?
Ned: He could easily do if for a couple more hours.

 

[Piscean]

For instance, I want to express how long two people have been married.

Don't use 'for instance' unless you are introducing an example of something you have just mentioned.