This will sound like a huge paradigm shift but I am against men helping women raise another mans child. I think to the best of everyone ability a man should be raising his own children. Statisitcally speaking, unrelated men are often very dangerous around children. Not to suggest that men cant be genuine and sincere but the frequency with which children are often molested, abused, killed, etc. it is usually at the hands of an unrelated male who was/is involved with the mother. To add, these relationships are usually temporary. As genuine and heartfelt as a man is, its difficult for him to be raising children that aren't his. He also has little incentive to stay so these relationships are too fragile. Imagine being a child of a dating mother and having men in and out of the house. Its not healthy, its dangerous.
Its already traumatic enough to not have your father around but then to add and stranger to the mix is too much stress for the children. I understand women want companionship, support, and love but Im weary of unrelated men around children assuming responsibiltiies that aren't his.