The most typical advice for dealing with an emotionally unavailable partner is to either accept him the way he is or walk away from the relationship, because he will never change, unless he wants to. If the emotionally unavailable man in your life has actually told you he wants to change, you may have a rare opportunity to help him do it.
Deeply Buried Causes
The first thing to understand about emotional unavailability is that it serves a purpose, and the second is that it isn't a deliberate choice but a subconscious compulsion. The purpose it serves is to protect a person who has been badly hurt from being hurt again. If the man in your life is emotionally unavailable, he probably experienced something in his upbringing or other life experiences that made emotion and intimacy seem highly threatening to him. Because of his deep fear of being really close to another human being and suffering the potential consequences of abandonment, betrayal or heartbreak, he remains walled-off inside and can't connect on a deeper level even if he wants to.
Facing the Fear
If the man you're dating wants to open up and get truly close to you, he has to face the fear inside of himself. That's not an easy thing to do, and the attempt can bring up a lot of buried negative emotions. Ask him to think about his life and the relationship patterns he has seen or has experienced in the past. Encourage him to face his fears of being betrayed or abandoned, and let him know that you'll be there for him as he goes through this process.
Intimacy and vulnerability are closely connected, and one isn't really possible without the other. If you encourage a man who has never dealt with his deepest emotions to become more vulnerable, you should expect it to be hard for him. He will have to look deep inside and face painful things he hasn't thought about consciously in a long time. The safer he feels to talk about the hard things with you, the more intimate the two of you will become -- but if he feels judged by your reaction, he will probably retreat behind his walls again.
Doing Things Differently
Facing the fear inside is the hard part. Changing the patterns that keep him distant should be relatively easy. Ask your man what he thinks he does to keep himself unavailable and what he would need to do to become more available. He may acknowledge that he works more hours than he really needs to, that he plays video games excessively or spends too much time out at bars or nightclubs. There's nothing wrong with working hard, playing games or socializing, but any of these can be used as ways to avoid getting closer to you. All he has to do to improve the situation is to consciously choose to make more time for your relationship.