My husband found his birth family and I'm struggling badly

I've been with my husband for 13 years and we have 2 children together. We are both mid-30s now and feel well established in life as of recent. We've been building ourselves up a lot and working on our marriage and betterment of our relationship a lot in the past 2 years. We've spoken about him being adopted off and on over the course of our relationship and helped work out residual feelings caused by his adoption. He's always wanted to look but had anxiety and worries and finally now that we felt in a good position he started to look and he found them! I'm so exceptionally happy for him, that he has found his family, but I'm also drowning in sadness for myself. We have spoken at length about it, but I can't seem to find a way to shake the bad feelings I have. My husband is semi-estranged from his adoptive family (and mother passed away a few years ago) and now he has a massive amount of siblings and 2 birth parents all vying for his attention and love and he's giving it to them. He deserves to right? They all deserve this moment of love and happiness but it's all being taken away from me and our children. I hate that I feel selfish, I hate that I sound greedy, but this is my husband, this is the person I held crying for years because of the damage caused by his adoption. I was here and they weren't, I picked up the pieces and they didn't, and they are getting his unconditional love and I feel resentment towards them. He has been good about hearing me, but I don't feel like he can really understand the internal dilemma this is causing me and I'm scared its going to be the end of my marriage if I can't figure out how to let my husband love his new family. He's making plans to visit family and it's getting realer fast and I'm handling it the worst of everyone involved and I hate myself so much for it. I am desperate to talk to anyone who is going through something similar. A support group or anything?