OVERALL:
Time travel is really interesting, but can be very messy too. Since the writer is Yang Hee-Seung (Weightlifting Fairy Kim Bok-Joo, Oh my Ghost) you can look forward to see many funny moments and a very enjoyable drama but I couldn't take the drama seriously. The drama was too long. It could have just been 12 episodes....

STORY:
It is one of the typical time travel stories. I actually didn't like the concept of "it’s always the man's fault when there's trouble in the marriage".

CAST:
Jisung is an actor that makes the drama really enjoyable with his acting. I kinda liked his character, but he was selfish and no one actually talked about that, but then, he had such a good devolvement.
This is the first time I watch a work from Han Ji Min and she's so good, this role fits her so well.
Amazing support characters. They were so funny and refreshing.

[NEGATIVE POINTS]
--[SPOILERS]--
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(This is the part when he wanted to go back to the past.)
1) They lost their son and he didn't care. We just watched one short part when he felt "sorry".
2) His actions were not because of "jealousy", but because he was being selfish about how happy his "wife" and his best friend were together. He was always in the way of these two, because he didn't want his best friend and "wife" to end up as a couple, which is so selfish and childish.
3) His sister married his other friend and had a child, and he still didn't care about it.
4) He didn't think or cared for his "new" wife either.
But as I said, he had a really good devolvement.
5) Now a different problem: for me things got fucked when WooJin uses the coin to time travel. They could have removed that part....
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--[END OF SPOILERS]--

The drama had a really good ending!
Yes, I do recommend this drama. It was very enjoyable.