Allowing anger as an emotion without reacting to it

Hi Brooke,
I am having trouble allowing an emotion like anger without reacting to it. For example last night we talked to our 26 year old son and he let a girlfriend take advantage of him and gave her money he needed to pay his rent. He asked us for money and we paid the rent again for him as my husband co-signed on the lease. At the time we felt compassion for him and love and then I got angry and could not sleep. The thought was he is taking advantage of us. I felt the anger in my chest and entire body being tense and had trouble falling and staying asleep.
This morning I decided I wanted to feel peaceful and the thought that led me to this was: Chris is doing the best he can right now and we love him no matter what.
So how do I allow and feel anger without staying up all night? I felt like that did not serve me at all.