Shady/Red Flag?

This week my boyfriend told me he gave $100 to a former female “friend” he found attractive at one point. He told me he had helped her out financially 3 years ago “hoping to get something out of it” basically sex! She has been asking for money since December and he finally caved. She said she was gonna be thrown out to the streets. I appreciate that he told me but I’m very upset and hurt by it!!! It seems pretty shady to me! Am I over reacting?? Or is he acting shady?? Any advice is appreciated!