This character has an immediate deep impact on the audience, he will immediately arise strong feelings, especially if the reader is a woman.
Why is that? Because every woman has met at least one commitmentphobic man. Most likely, she has dated him and loved him and had her heart crashed by him. The result is a complex combination of empathy and distrust that will win your audience right away.
The commitmentphobic men (if you want to know more about the creators of the term and the subject, I strongly recommend the eye-opening book "He's scared, she's scared" by Steven Carter and Julia Sokol) is a person who is scared of long-term relationships, contracts or appointments.
The classic stereotypical exemplar of commitmentphobic man is very approachable to start with, probably attractive and easygoing, sometimes even too straightforward in his chasing women as well as life opportunities. After an enthusiastic beginning of hopeful, steady, increasing progress, our Lead character reaches a point where he feels that the relationship/job/project is stable and safe. Right away, he starts panicking.
At this point, the partner/colleague/friend of the commitmentphobic (in literature known as "side kick") starts receiving mixed signals, ambivalent feelings of love and fear, approach and withdrawal. One day the most loving, caring, attentive partner turns into an elusive shadow barely answering his phone.
Creating a commitmentphobic character will ensure you the full attention of your readers. They will to through their personal experience and use your novel to find out the "cure". They want to know if there is a "technique", some way or "method" to fix the commitmentphobic and turn him into a perfect husband/worker/partner in crime.
Is there such a "cure"?
Wouldn't you like to find out already? That's why it's gonna be a bestseller!
Have a good novel!