When people ignore their friends because they have relationships, they say to their friends that in fact they are not friends at all. True enough, sometimes it is hard when we first fall in love with someone to even think about spending time away from our lover and with our friends instead, but we must never forget the importance of maintaining all of our relationships. A true friend should be treated as a true friend.
Most true friends will be happy that you are in a relationship that makes you happy, but if they are someone that you truly love and care about it is imperative that you make at least some time to spend with them. Though they may be lower on your priority list, they are still on your priority list; you should treat them as such. Never ignore your friends because you have a relationship.