In this case, the main problem seems to pertain about correct technique of sexual intercourse. This can be easily corrected by reading some good book on techniques of sexual intercourse. These are available in all good book stores.
The other component of your problem pertains to inter-personal communication. Please do understand that good sex takes place only when partners care for each others feelings, sensitivity and needs. Sex does not occur in isolation. It is an extension of relationship between two partners. Please discuss with each other about the issue.