Your husband acts as he does because likely he has not forgiven yet. Forgiveness is both divine and difficult. How did he find out, did he discover it or did you come clean?
I agree with mitchzz that if he is unable to move forward after this long then outside professional assistance is needed. There is likely there are underlying feelings or thoughts he has not shared with you.
As far as the sex vs. kissing. Sex is only a physically act to him at this point, not an emotional bonding. There is a difference between f***ing your spouse and making love to them. Kissing you and telling you he loves you is an emotional function.
Finally, how is the rest of your marriage. Communication, decision making, spending time alone as a couple, physical intimacy? Do you function as a married couple or roommates. And do you feel he is keeping the affair as a trump card to continue to punish you?
He found out because the other guy told him.
As far as talking to a professional, he refuses. He won't even talk to me about it when I bring it up, much less will he talk to someone else. He literally will just ignore me or say "not now" whenever I try to bring it up.
My husband isn't the kind of person to have sex just to have it. Believe me, he has proven that before. Even before we started dating, that was a big thing with him, that he would never have sex with someone that he doesn't love. We have gone for 6 months without doing anything and it didn't seem to bother him.
You ask if we function as a married couple...that's kind of hard to answer because to me the kissing and the "I love you's" are a big part of what I would consider functioning properly as a married couple. We go out to dinner, we go to bars, we spend nights together minus the child, we don't really argue about much else other than normal everyday stuff like he needs to change the litter box, don't go to Dunkin Donuts every morning when there is plenty to eat at home, that he doesn't appreciate all that I do around the house...you know, stupid stuff like that. The only major fights we ever have are about how I feel that since all this happened, that we have gotten absolutely nowhere and at this point, I don't know if we ever will.
I'm only 23 years old. I don't want to waste what could be the best years for me and my daughter on someone who doesn't appreciate anything I do or any effort I make. I do feel like a roommate sometimes. I cook, I clean, I do laundry, I work 40 hours a week (as does he)...but in the end, all I get out of it is cleaning up the dinner dishes, coming home at 9pm from work and finding the house a mess, and occasionally, we have sex, which I am the one ALWAYS making the first move. I don't get what I really want from this marriage, which I think are some of the more simple things to do. I don't want a million dollars, I don't want a fancy house or car. I just want him to say he loves me. And I can't get that unless I force it out of him.
Oh, and btw, Thursday is our 4 year wedding anniversary. Let's see how well that goes.