Been in your situation, but I am a guy so I will give you my take on it.
Did you ever get on your anti-depressants? You said you were thinking about it. I personally never did this, but I know that it was absolutely HELL to concentrate on anything but this for awhile and maybe that would have helped.
About your H....you acted on a suspicion of OW. I think instincts are right the majority of the time, and there did end up being an OW anyway. Now your H is having the time of his life, getting to "date" around, and getting the person he was in love with too.
You also said that you were "clingy", that you called him crying a few times, etc and wondered if that was why he might be avoiding you. The answer is a resounding YES in my opinion. This guy is loving his freedom, and when you call it drags him down when you are that way, so it is probably easier to avoid you. This is the whole reason for you to DB.
I think you said when you went dark he was calling you and wanting to come back. I would recommend that you set some goals for yourself and stick to them. Decide on a course of action and stick to it.
1. Don't be available to him. This sounds weird, but you saw before when you weren't so available he chased you. So when he does start chasing you....
2. Be cool to him. Doesn't mean you can't be friendly, just don't be physical and no R talk whatsoever. Act as if you have something else going on in your life to make you happy. Which leads to.....
3. Get something else in your life to make you happy! Could be getting more involved with your son's activities, joining a bowling, darts, pool etc league, taking cooking classes, dance lessons, working out, etc. Take up your freetime with things such as this. It won't let you mope around thinking about him, will make you feel better and make it easier to deal with this whole situation.
Remember when you two first met? You had other things in your life going on, it wasn't centered on him. Get back to that. He is doing the same thing right now, you should be too.
I am not saying that the above will get your H back, you might not end up together anyway. You will however be happier, and you will have a shot at your H. What you are doing now isn't working and you feel badly. This way you feel good about life, and will see that there are other things/people out there for you to interact with and care about.
You deserve better. Only you can make it better though. You can't control your H, so quit worrying about him. Control what happens to you.
