Why do men always seem to take advantange of woman after a date or no date?

I am a grown woman in my late 30's. Unfortunately I broke my ankle and had to have surgery and 7 screws put it my ankle. I am obviously in a vulnerable stage- not driving and being incapacitated for 2 mths- yet I have been in touch with this guy same age who used to go to High School with me. So, we flirt on the phone and text and i finally get my cast off...he has been asking me out when I am not really mobile..so we finally go to a big lunch and nice time and (I am big ed attractive curvy woman) so he is talking about how he is a fireman ( I think he is a EMT) and he braggs..and he is talking jokingly about how good he is in bed and how well endowed he is. He payed for my lunch, was a gentleman on accomodating me with my crutches and pulling up to the curve for me then when we get back to my apt- he has to help carry my crutches up and (I think in my mind) oh he can watch TV with me- so he comes onto me strong and I felt after a while obligated to sleep with him. WHY WHY WHY I am so vulnerable now...I told him no at first- but I felt attracted to him..and he kinda was pushy and took me to my room...so then after a few laughing and "no" he is like why not- we flirt on the text for months- i take u to nice lunch and take my day off for you...oh gosh..help me- now I feel awful- but it was very good! LOL = why would a man do that to someoen with a broken ankle?