Hi Dee, sounds like a 4th Step is really going to help you.
A few things:
1. forget the old 4th step, its gone, if some of the things from that are still relevant today, then put them in.
2. chronological order is not important, completing the columns as columns is, don't be tempted to work sideways, always downwards!
3. Its about stock in trade what resentments/fears/sex harms still bug you TODAY. If little Johnny wouldn't kiss you in 9th grade, who cares!
4. Keep it simple, don't write your lifes story and a 10 page essay for each item in inventory. Stick to the points mentioned in the Big Book.
5. Do not be frightened, a while of discomfort to do this is worth a lifetimes freedom
6. Be thorough, how free do you want to be?
7. You mention resentments on your dead husband, they are relevant, and should be included. You don't however confront anyone here! You look for your part in it, your sponsor will help.
Sounds like you have a lot to work with on his son/wife.
quick example on them, you resent them for not helping. Isn't the fact that they didn't do that their business. Maybe they couldn't deal emotionally, maybe acting mean was their way to deal with it. How do you know? maybe seeing your husband dieing was making them spiritually sick. Could expecting them to behave how you think they should be a little dishonest or inconsiderate of their feelings? Were you protecting your self esteem by painting them as the bad guys to hide your fears? Who says how things shoulg be done, you or GOD? Their role in the resentment is of no importance to your inventory. The son begging for a relationship, his issue, don't take his inventory, that is playing god.
Enough from me, I know nothing, but there are more ways than one to play a part in a resentment!
There's no magic get started thing, you just have to ask yourself how bad you want whats on the other side of doing the step, and if you are willing to go to any lengths for sobriety.
Just remember it feels great to get through steps 4 and 5 if you do them carefully and thoroughly, I've never met anyone who regretted doing them well!!
I wish you lots of success and welness, hope you get through it, and thanks for helping me by letting me share.