In most general sense, "bastard" can be an equivalent and it seems like the most universal term. (even in some other languages)
As in "You bastard!" versus "You bitch!". But there can still be different senses between them. It depends on the situation.
use as a vulgar term of abuse for a man is attested from 1830
I even found passages that support my answer from publications of professional people.
From the book "Emancipatory Movements in Composition: The Rhetoric of Possibility"
By Andrea Greenbaum (2012):
From the book "The Anatomy of Swearing" By Ashley Montagu (1967) (Note: Even ~50 year ago, there is the same idea)
There is manwhore also for an equivalent of the original sense:
(slang) A man who sells his body for money; a male prostitute.
(slang) A promiscuous man who has no regard for his sexual partners or the emotional value of his relationships.
Note: This is more of an equivalent of "slut" in modern usage. Slut is even used for men sometimes.
Wikipedia also says: (for "bitch")
Its original use as a vulgarism, documented to the fourteenth century, suggested high sexual desire in a woman, comparable to a dog in heat. The range of meanings has expanded in modern usage.
There is even the term "man bitch" according to urbandictionary. (Note: This usage is not common though.)
A man that acts like a bitch. Malicious, unpleasant selfish person; especially like a woman. Weak or comtemptible.