Becoming a significant part of the children's life too quickly will cause enough stress to curtail any opportunity for the relationship to flourish. Take time to know one another apart from the children. Spend time building the length of time you are together with the children and their mother. Getting to know one another will take longer in this situation because there are more people's needs to consider. There is no such thing as instant intimacy or instant family.
Emotional attachments take time to solidify.
Trust develops through experience and there are no shortcuts. You are considering yourself when you allow the relationship to mature slowly and with realistic boundaries. Watch this report about showing affection to boys. Find out here. You should not rely on this information as a substitute for personal medical attention, diagnosis or hands-on treatment.