I have worked in an office all my working life, and I learned very quickly that you cannot keep an office romance secret. Somehow it gets out. I don't know whether the behaviour between the two of you changes, but it doesn't take long for people to become aware of the situation.
This is OK if both of you are not married or with a partner. However, it makes the situation tense in the office when either or both of you are married, and an affair starts.
It usually ends in a major hassle and often in one or both of the participants leaving or being sacked. It becomes even worse if the partners or spouses of the participants find out.