Summarize this article in one sentence.
Your ex may try to come back into your life when they need attention or intimacy. Verbalize to your ex that “over means over” and refuse to allow the person to drop in and out of your life.  Turn down the offer if they ask you to hang out one-on-one or have sex. This also means communicating your boundaries when the person expects you to drop everything to see them or interferes with your other relationships. Try to discontinue any joint activities that the two of you may have shared. Your ex may think that you two can continue some of these even though you have broken up. You will need to choose to discontinue them, or find new outlets away from your ex. If you've been in a relationship for an extended period of time, you may have been neglecting your self-care. Use your new single status to make yourself number one.  Do all of the things that you've always wanted to do but never did in your relationship. Take yourself out to new and interesting restaurants, browse around art galleries, and attend concerts. On your self-dates, be sure to look your very best just as you would on a regular date. Get a new haircut or try out a new signature scent. Your self-esteem can take a hit after a breakup. Remind yourself how worthy you are by surrounding yourself with positive, supportive people.  If you lack a strong support system, try joining a new club or organization in your area. You could also try to rekindle and rebuild relationships that you may have neglected while you were with your ex. Think of one small way to challenge yourself and do it. Taking even a minor risk can make you feel empowered.  Take self-defense, sign up for a cooking class, complete a certification for your job, or wear brighter colors in your everyday wardrobe. Switching things up can make you feel brand new. You could also try journaling. This can be a valuable outlet for your feelings.

Summary:
Set strong boundaries with your ex. Date yourself for a while. Spend time with people who build you up. Try something new.