Dating a womanizer requires accepting his past and being aware of the traits that made him a Casanova. If your boyfriend has spent most of his dating life chasing women, it might be hard for him to settle down into a monogamous relationship. On the other hand, you shouldn't judge him on his past, but rather how he is with you -- in the present.

Manipulation Skills

A womanizer may have very well-developed manipulation skills that served him well while he was chasing women. Most womanizers are intuitive about emotions, but they use them as weapons against the women they seek, says psychology professor Robert Hare, as cited in the "Psychology Today" article "Field Guide to the Casanova: The Lady-killer Files." Be sure to have clear boundaries in your relationship with a womanizer. If he blows hot and cold with his love and affection in an attempt to control you, don't give in. If he says, "If you loved me you would ..." reply with, "If you loved me you wouldn't ask me to ..." Stand your ground, or you risk being trampled in this type of relationship.

Shallow Emotions

Some womanizers move from woman to woman because they have shallow emotions and are only looking for a physical connection, says Hare. If you get the sense that the man you are dating is not looking for an emotional connection, don't expect him to give you something of which he is not capable. Some men have trouble forging a romantic bond, or it may take them longer to become emotionally connected. Be realistic about what you will get from the relationship, and you won't set yourself up for disappointment.

Self-Esteem Issues

Often womanizing ways are the result of self-esteem or insecurity issues, according to psychotherapist Jed Diamond, as cited in the "Psychology Today" article. It could be that your womanizer was a geeky teenager or late bloomer, and he tried to make up for lost time and feelings of not measuring up early in life. In these instances, you can help the situation by helping to build his self-esteem. Let him know how he meets your needs with simple statements such as, "I feel good when I am with you," or "I really enjoy your company."

Current Behavior

In the end, you can only judge your partner based on the behavior that you see in the present, says psychologist Barton Goldsmith, as cited in the "Cosmopolitan" article "So, You’re Dating a Former Womanizer …" If he is treating you well, showing respect and making accommodations in the relationship, it is possible that he has left his womanizing in the past. Try to live in the present and avoid ruminating about what he might have been involved in. Unless there is a problem to solve, you will only create more worry for yourself by thinking about his past.