90% of being emotionally available is being willing to listen, really listen, and only listen. You don't have to figure things out. You just have to be willing to be told someone else's point of view, without letting your attention wander elsewhere, and let them have their point of view without interference or judgment from you, 100%. "Just"...:rolleyes: :D This is truly a rare gift. Few really ever give it or ever get it.
If you want to be emotionally available to your wife, start with listening. Help her to catch up on whatever chore of the moment has her running around. When you're finished, sit down with her on the love seat or the couch, rub her feet if she likes that, keep the physical contact on the "G" or "PG" level, and ask her to tell you about her day. Let more intimate physical contact wait for another day or another time, unless she initiates it. You might ask questions just to encourage her to clarify or to expand on what she's saying, to allow her to explain how things make her feel in a way that you might understand, but DO NOT try to solve any "problems". DO NOT venture that she ought to feel some other way. The feedback ought to be more along the lines of "that sounds hard" or "that sounds wonderful." Just help her to feel comfortable and listen.
One rule: she has to be gentle in teaching you how she would like you to listen. This is a new skill, and not natural to you, but as long as you're willing to try, ask her to be patient. Also, if she does want you to do something for her or to brainstorm on solutions, she has to issue an invitation. Otherwise, you have to assume she wants to share her problems or her victories with you, but that she wants deal with them herself.
I think Marriage Encounter might help you out, too. I've known a lot of guys who dreaded going, had to be dragged kicking and screaming, who attempted to bribe their way out of it the whole way, but who came away saying it was the best thing they ever did.