DP has a DS from a previous relationship. His partner at the time chose to end the relationship as soon as she found out she was pregnant on the basis that she 'no longer liked DP'. Although DP had some contact with his DS during his early years this eventually stopped due to DS's mother being repeatedly obstructive regarding contact. We do not know what reasons she has given DS regarding the ending of their relationship or contact or what else she might have told him true or otherwise.
DP and I now have 2 children together aged 2 and 4 and I am aware that at some point DP's DS1 may make contact. I am wondering how to introduce his existence to our 2 young children and how to deal with the possibility of contact from him in the future.
This is a tricky one but perhaps simple at the same time. I would talk to your children about their brother to the same extent that you do with your dh ie not keep it a secret. I think children tend to take things at face value and if that is how it is, that is how it is. I have a similar issue in that we have a ds, who has a half sister in London and one in Australia. I am now the 3rd woman dp has had a child with. DS's sisters are 17 and 19 so they are a generation apart! I plan to just talk to ds about his sisters and make it a "normal" thing.
Has there been no contact at all? Are there any photos that you can show them and say "that is your brother?"
Does your DP know DS address? Does he want to make contact? What might be nice is if he just sent a birthday card and christmas card every year so that ds knew that he was thought of and he could make contact when ever he is ready. Send it by recorded delivery so that if they never get to him due to BM then at least if he did make contact and asked why DP never tried then he would know the truth...Good luck