Paraphrased/borrowed from this excellent comment

Men and woman on average have different sacrifices and rewards at different periods of marriage and relationships.

In the courtship phase it's typically men making more sacrifices, paying for dates, initiating, entertaining, doing the romantic labor etc.

During cohabitation it's the woman typically making the sacrifice because she is no longer getting the one way treatment of the initial stage but she is doing more housework and emotional labor than the guy and not getting the title nor the economic benefits of wife.

The wedding is something the woman typically dream of not men, now she is winning, getting what she wants, the proposal, the ring, the wedding the honeymoon, the tile of wife, the social recognition and the access to his finances (which are on average better)

Once she gets pregnant and gives birth the woman benefits from having a husband, and he must sacrifice and supporting her, loses sex for a long time, has to invest a lot of time effort and headache into her while she does nothing much for him over that period of time.

He would be better off single during that time and she would be worse off single during that time.

As they get older it's the man's turn to benefit since he typically loses his health sooner and requires more care and she typically does more of the housework and emotional labor anyway.

In a typical life cycle, both men and woman make different sacrifices and get different benefits over the course of their married lives.

So if a woman uses a guy to fulfill her imperatives, and gets her proposal her ring, her dream marriage, her honeymoon, her 50% of what he owns, his support for pregnancy and early childhood then walks out on him and takes the kids leaving him with nothing to show for his investment and the prospect of growing old and decrepit with nobody to support him, the man has sacrificed for NOTHING