Sorry for that uncomfortable situation. Funerals do bring out a lot of emotions but it certainly sounds like you BOTH have a ton of unresolved issues that never got dealt with and that might explain why she was so cold. The fact you moved into a new relationship so quickly is another reason she might be hostile towards you even if it was her who wanted the divorce.
Have you been to counselling? It really can help. Time is a great healer too but time spent working on yourself and your issues is best. Jumping into a new relationship too soon just masks the problems. It's a great bandaid but when you rip the bandaid off - you're still bleeding.
But only you can decide where to go next. Obviously not anywhere near your ex. And what about your kids? You mention your son at the funeral. How is your relationship with your kids and how do they feel about your new girlfriend?
