I understand your anxiety over the issue but let me tell you very basic thing about the solutions of sexual problems. Get relaxed first, so far you and your partner remain tense your problem is going to worsen. Second thing is you need to have patience because it may take some time to revive the “spark”. Men are interested in the act and women are interested in the time spend during the act. Therefore, to charge a woman foreplay is very important and to give her feeling of satisfaction after play is very important. As per your mail, there is little foreplay between you so spend more time on that. For initial few days just foreplay and not an act can be good idea. You like it fast, have you said this to him? You should be very divulging about your preferences during the act. You may take help of good romantic background music and/or some erotic movies to excite yourself. Sizes are psychological; it really does not matter much in passionate act. Dreaming up your excitement through imagination (of act, of another partner etc.) can also help you. Discuss your feeling of insecurity with him and seek his sympathetic support in solving this problem. You may have some other underlying emotional issues, may be in subconscious mind. It is not a bad idea at all to seek some professional help if these things do not work out.