Dating

Can you be friends with an ex?

So due to a mutual person passing away, me and my ex (2 years ago) came back into contact. We discussed how our lives have been since, mine has gotten pretty good whereas hers seems to be worse.
For around 5 days we talked in a friendly manner before Christmas and agreed that we should meet up for a coffee at some point. The next day she sent a paragraph about me not coming back into her life like a wrecking ball and we should leave us in the past (she left me and cheated on me 🤷🏻‍♂️)
I obliged and did not message again. 3 weeks later (January 2nd) she randomly text me and asked if I wanted to do a hiking challenge with her this year. I left it a couple of days but said sure and we agreed this June. Since that any slight effort I’ve made to be friendly has been met with a brick wall. 2 or 3 word answers or just ignoring the message.
I haven’t given any hint of wanting to get back with her and the messages were just about generic life.
Can you be friends with an ex?
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