Heart broken for my kids...

I have an 11 yr old daughter and a 10 yr old son they LOVE LOVE LOVE my ex bf we broke up do to lots of misunderstandings and other family members budding into my relationship. He has no kids, he loves them, but not like he should love them for the amount of time we’re together and not only that we were friends before we dated so he has seen them grow, my kids want us to get back, they don’t want to loose him. My daughter has been building up anger and hurt and tells me she wants to tell him she loves him but it hurts her to say it. My son always comes home and goes directly to him first to say how was your day and hug him. The kids have a relationship with their dad, which is not the greatest, they are closer to my ex. I am getting the kids halo, and healing but I would also like to get something so that my ex would return the same amount of love to the kids. What do you guys thinks?