When you talk to him...do you keep your anger under control? I've noticed you've mentioned in some other posts that you can tend to go off (well who wouldn't right?). If you go off at him...and say that the next time he does this something will happen, and then don't follow-through he's learning his behavior is ok (no matter what you say). You'll get angry, you'll make threats....but really nothing happens.
There are things you can do.......such as packing his bags when he's gone after you find he's visited the site yet again.....and leave them by the curb for him (I mean toiletries and everything....clean out his closet, use trash bags if necessary), then lock the door....heck change the locks if you need to. If he chooses to straighten up....you can always give him the keys. But, tell him what he would have to do to get eventually get back in.....counseling etc. I know right now you feel like your feelings for him are gone, and boy-o-boy do I understand that.....but they may just be buried really deep under all that hurt, anger, and resentment.....that is what I found a year after my XH and I split. FYI, he and I are now good friends, had he not been dating his current W for a bit when I finally realized I wasn't angry anymore....we'd probably still be together now.
If we had children together I would have probably worked much harder at reconciling....but for me it definitely would have required a temporary separation. Perhaps that's what you need....space & a bit of time to get over the hurt/anger. Counseling (if he agrees) during that time can be instrumental at reconstructing your M & your family.
I guess what I'm saying is this.....there are definitely things you can do to reinforce your boudnaries....but don't jump straight to the big "D".....unless that's what YOU are sure YOU want.
