I really want to have sex. But, my boyfriend isn't ready and he said I could have sex with my ex who left me because I wasn't ready. I need to know if i should or not?

I'm very embarrassed to say that over the last year I have been very promiscuous, as in to having sex with 15 different partners. I have gotten over that phase, and I have sworn to stay celibate for at least six months. My question is whether or not it is possible for me to be tight again? Also, if it would be right for me to make a future boyfriend wait a while, before having sex with him? I mean, I gave it up to someone I just met, why would I make my 'boyfriend' wait? Please help, I feel so horrible with myself. I think that staying celibate will help me regain respect with myself, but, of course, I can never forget it.