So I'm messaging this girl and we're getting really close and sexual video calling, but she was dating an another guy before we met and now says she's dating him so blocked me.

She then unblocked me after I asked her to, and has now blocked me again, "for the health of her relationship".

I don't know the guy she's dating but I strongly suspect he's a half wit and just fucking with her based on his facebook photos.

I think he'll be out of the picture before too long and I think she'd go for me.
How do I get her to unblock me?

This is the text I'm thinking of sending her,
"Sarah it's clear that your relationship with Dan is your priority and I respect that.

For whatever reason, you feel Dan is a better man for you than me.

However, blocking me from your life is not going to help you have a healthy relationship.

All you had to do is tell me your decision and I would have respected that and kept my distance.

You have no need to block me for ever and you don't need to lose my friendship."

Would this have a chance of working or is there anything I can do to improve my chances of a positive response?