Unfortunately there are many people who have a pattern of telling lies, and when you find this out - then look after yourself, because they are not going to care about you.
I know people like this, I can see it happen. I don't understand it.
But, once they get to know you, then they know what to lie about, they know what you will believe, they know how you will react (and they learn about others too).
Will they change? Don't count on it.
And consider yourself lucky that you have found out now before things are worse.