This is a Lifetime original movie of sorts.
Basically, the beginning of the movie shows two people - a man and a woman, getting married and their honeymoon thereafter.
A month after the honeymoon it turns out she is pregnant, which comes to a surprise for the husband. Flashback to when he got a vasectomy a month before the wedding. it turns out he was lying to her about wanting to have children in the first place, although the house they bought together could easily have lots of children.
When he confronts her about the vasectomy she tells him that she cheated on him with a more handsome and wealthy man. He storms off and goes to a bar with his friends, and gets himself into a one-night stand.
She's at home contemplating her future with her husband, who she had known since high school, or this new guy who she only knew for a few months, as a friend of a friend from someone at her work.
When he comes home she makes up her mind and asks him to get a paternity test, just to be sure. He is unsure because he enjoyed his time being single, again, for that night. He tells her about what happened and she gets violently angry at him, but when he tells her she did the same she calms down.
They get the test done and it turns out that the husband is actually the father. The vasectomy worked but there was extra semen left after the procedure. They talk about it and he decides to get a reverse-vasectomy.
Flash forward to the delivery. The husband helps her as much as he can through the delivery. The baby comes out and they name her/him (yet to be decided).
A month after the pregnancy the couple decides to renew their vows, and have a second wedding. This time it is a private wedding, with just them and a minister who happens to be their best friend.
They go on a secluded second honeymoon up north to Canada in a log cabin and fish, hike, and hunt for two weeks.
After a month of getting home it turns out she is pregnant again, and the closing line of the film is, "this is our promise renewed."