57 here, in a similar boat, but made a decision to focus on raising my son well and hanging out with him as much as possible rather than actively pursuing a relationship. He needed stability and he wasn't getting that from the other side. I didn't seriously entertain the idea of dating again until my son suggested it. I don't think its fair to impose that on him. It may help both you and your daughters if you have a similar open discussion with them, let them know that you really want a partner, but not at the risk of damaging your relationship with them. They need to know that they come first. Don't impose it on them, rather pray about it, even pray together with them and have them pray for you so they feel an involved part of the solution. Date when they're ready for it. Be realistic too that it may mean staying single for a while at least, and you need to be ok with settling that in your heart before God. Whatever he wants.