I don't think it's a problem or anything. He should be happy that you are wet which is a sign that you are enjoying the physical intimacy. You can try changing position so that it stimulates him more. Also indulging in more foreplay and if comfortable with oral sex you can try that as well. Plus find out whether he is on some medicine that causes delayed ejaculation. With change in ya regular act of love making I think you both will be able to sort the problem out. Be communicative with your partner.