Of course, only you can make a decision about your child. But in my experience, openness and honesty is rewarded with respect. On the other hand, secrecy and deception fosters anger and resentment.
Your child will love you no less with the knowledge about his or her conception. It does not threaten the family unit at all, but inspires new connections. Take a look at this Science Daily article: “Re-shaping The Family: What Happens When Parents Seek Siblings Of Their Donor-conceived Children“.
Parents who have conceived children with the help of sperm or egg donors and then try to find the egg donors — and also other children conceived with the donors’ help — often end up creating new forms of extended families, according to new research.