Wow. Where to begin.

First off I don't really think poorly of you. I have been in the same scenario and I know from experience that when you aren't getting those feelings from your marriage it is hard to resist them when they come from somewhere else. We all just want to be loved and sometimes it doesn't matter how we get it. Just know that you're not the only person out there that's going through this.

As for your marriage well that is your problem to work through. It really doesn't matter why you got married because that was your choice and you need to own it and not use it as an excuse. If your marriage is loveless and un-fulfilling then you should end it. (yes I realize the irony of me saying that because of my current situation) I realize that is easier said then done but you can survive it. You chose to stay so you can choose to leave. I don't say any of this to be critical but rather when we lay everything bare only then are we equipped to make the best choices for ourselves.

Finally he may have had a role in you doing this but ultimately it was your decision. We have to own all our choices and the fruits they bear. You could have decided not to do it but you didn't. I'm not judging your decision as I have been there but just want you to understand that it was a choice. Now you need to figure out why you did it and what bearing it has on the relationship and or the future of the relationship. You didn't mention kids so if there are none then it should make it easier but please remember to make sure that you make the decision that you need to make. Not the one that you think is easiest for him.