TinyPangolin

My partner (we are unmarried and not in a civil partnership) and I have lived together for a number of years. During that time, I bought a property in my name. They send me money most months. They have referred to it as rent at times and a cash gift at others. Sometimes it has fluctuated if they send me money for a holiday or large joint purchase. We don’t have any rental/tenancy agreement in place. Do I need to declare this income, or send HMRC any forms?