Sign #1 - You no longer have sex
If sex is non-existent in your relationship then that is a pretty good sign that your sex life needs to be improved. The first thing you need to do is figure out why you are not longer having sex. What issues are getting in the way? Is it work? Is it family? Figure out exactly what it is. This is the best way to fix the problem.
Sign #2 - How often do you have sex with your partner?
If you and your partner aren't being intimate on a regular basis then that is a sure sign that your sex life may need a little improving. Remember that each relationship is different. You will need to get with your partner and determine how many times you would like to be intimate with each other on a weekly basis. This will take a little compromising on both ends. You will have to take a lot of things into consideration such as your work schedule and your children if you have any. Whatever the case may be remember to always make time for intimacy. It is a vital part of a healthy relationship.
Sign #3 - Sex is boring and dull
If you are no longer excited about being intimate with your partner then that is a sign that your sex life may need improving. When sex becomes more of a chore rather then something you enjoy doing with your partner then some changes need to be made IMMEDIATLEY! You should be excited about having sex with your partner.
Sign #4 - Are you and your partner growing distant?
If so this could be a sign that your sex life needs to be improved. Though your relationship should not resolve around sex, it should be considered an important part. Use the bedroom to help bring you and your partner closer together. As your sex life improves you might also see other parts of your relationship improve as well.
If any of the above signs describe your sex life then you should consider making a few changes. Make time for sex. Experiment more and consider trying a new position or even a sex toy. Remember to stay open minded.