If she starts asking you the tough questions ("are you contemplating marriage?"), be honest but stress that she is your priority and you will never do anything that will compromise her happiness or security.
• If he has children too, your daughter needs some special reassurance of your place in her heart. As Rick and Lily discovered on Once and Again, it's necessary to help your child not feel threatened by your beau's offspring. You don't want your daughter to feel pressure to meet and like his kids -- although they will have to meet eventually. Perhaps you can schedule a casual pizza dinner for both families (it worked on Once and Again). Ask your daughter to be on her best behavior at this event but to vent her feelings about it to you before and after. If his kids are confused and resentful about your relationship, tell your daughter that she's not alone -- at least they'll all have a common bond! Again, the ground rules for the mingling of the families is fluid, subject to frequent discussions and changes, if necessary.
• If you and your boyfriend break up, you have to break it to your daughter. It happens. Love doesn't always work out. It's okay to let your daughter know you're upset, but you don't want her to see you falling apart. If she developed a relationship with your ex-boyfriend, is it okay for her to have contact with him now? Give her the reasons (the PG version) for the end of the relationship. Use this as a springboard to a discussion on the nature of love -- how sometimes it is painful but it is a vital part of life. Tell her that after a mourning period you plan on re-entering the dating scene.