Please help me understand

Why do I let myself be picked on by my family and have my feelings thrown away whenever they seem fit?
Just a few details-
1.My sister phoned the other day and started picking at me about my first husband.
2.My first husband is not in my life unless he wants to see his children.
This, after my husband Michael (love of my life) has only been dead for 3 months.
3.year's ago,a social worker found me,cos my sister said she had a sister who lived in my town,social services wrote to all the jeanettes in my town,untill they found me,my 18 month old nephew was taking into care, when he went into care,he had scabies, lice infected (they were jumping off of him) and impetigo. I hadn?t seen her for a year so I didn?t know he was neglected.my other sister,brother and mum,blammed me saying i had him taken away from his mum,but yet they never said a word,untill two day's before x mas day,
4. I had him most of the time until he was 6 months old, and provided everything for him, if I had known he was being neglected I would have reported her, for his sake.
5.I wanted to adopt him because of the earlier bond.
6.I couldn't since my dad is a sex offender(I never see him),they had been thinking this for 12 yrs, yet not one of them said anything to me, my mum, my brother or my sisters.
7.I looked after my nephew, provided lots of thing's he had as a baby.
8.They do family scrapbooks for young children, I supplied everything he would need in his life, especially love.
9.My eldest sister had another baby who was taken at birth and went into cold turkey from her drug abuse at a day old.
She had all maternal rights taken away for both children. I am the only one to have contact with the child I took care of.
I wrote a letter once, I wrote to his adopted parent's. I explained that if he was receiving yearly letters from me, it may unsettle him.
I would not make contact, but could they give him my name and address when or if he wanted to contact someone.
This sis also had her first baby adopted, he would be 29.

Why is she doing this now after all of these years? Am I wrong to think by now it is because I wanted to go to college, which I did, got good qualifications, and worked in the field I wanted.
My last job accommodated me. Both my boy's are very bright. The eldest wants to be a special needs nurse, the other in the care field of some sort. I worked for social services looking after special needs children. I?ve thought nothing of helping these kids. Their mates see my kid's well educated, respectful and polite.

I nearly died in August. The only one who came to the hospital was my cousin. My mum did phone. In the month Michael died, the only family I saw was my cousin and a friend whom I call my 2nd mum.
My own mum didn't even phone between the day Michael died until his funeral , she cried for her aunt who died in April. Not a tear for her daughter.
Her grandchildren were close to collapsing.
Am I wrong to believe they still hold so much resentment because of all that happened in those early years? How does a mother and sister hold a grudge for so many years or is it just jealousy? I?m very confused. What do you think is going on, I could use some input and support? Thank you so much for reading. The pain is more than I can bear.