For one thing, as you said in a previous post... cut yourself off from them. If staying in contact with them immediately after a breakup makes it difficult for you to sort through your feelings and heal from the ending of the relationship, you need to be out of contact with them.
In some ways, I would compare a breakup with major surgery. You've just had a huge piece of your life (and possibly your heart and even soul) removed. Just as you wouldn't expect to recover from, say, a heart transplant instantly, but would give yourself several weeks to rest and for the incision to heal, you could give yourself several weeks for the emotional "incision" of the breakup to heal before you start trying to form a friendship.
If you're the one standing in the way of you taking a break from contact with them, you're the only one who can change it. The 40-day thing, I think, is reasonable. If you don't think you can handle 40 days, try at least 30; anything less, and I think you might still be stuck in the swirling emotions of still loving them, still hurting from the breakup, etc. And it might not be *easy*, but it is feasible: for those 30 or 40 days, don't hang out with the group of friends they're also friends with. Or check with someone else before each get-together to see whether the couple will be there, and if they will, stay home. It isn't a choice you *want* to make, but it is a choice.
But in addition to deciding "how to get better at breakups", I think one thing Angelina meant, and one thing that definitely stands out to me... stop saying you're bad at them! You're the one thinking "I'm really bad at breakups so this is going to be hard." Shift your thinking. Instead of "I"m bad at breakups," try "Breakups have been hard for me in the past, but I've learned a lot since last time, so I'm going to try to handle this one more effectively and in a way that's healthier for me."
If you identify yourself as "bad at breakups," you're closing the door to finding a better way to deal with them, because you're essentially surrendering control over your own behavior and ability to change it. You're saying "this is how it always has been, is now, and always will be." You have the power to change how you deal with things. Throwing up your hands and saying "I'm bad at them," or asking us to tell you how to get better at them instead of looking for solutions within yourself, isn't going to help you.
As for the thing with your husband, you say he has you in limbo. (That's a seriously suckish emotional place to be... been there, hated it.) I would set a firm deadline with him. While you obviously don't want your marriage to end, you and he are both in a yucky place right now, so I would say, "I know you're trying to make a decision, but until you do, we're both stuck. By (end of October; three weeks from now; whatever time you think is reasonable), I want us to sit down and make a final decision about where our marriage is."
And by the way... just as with my situation, your husband isn't keeping you in limbo. YOU are keeping you in limbo by choosing to stay and not ask for a definite answer from him. Take control of your life; it isn't easy, but it's a hell of a lot better than sitting back and waiting to see what other people do.
My loving (or not) someone is not contingent upon me having the relationship shape with them that I'd ideally like. 