<human>: Condense the text into a few key points

So I work in a *tiny* office. It used to be me, my actual boss [35M] and his dad but the son has since moved to another state. So for the foreseeable future unless we expand, it is going to be just me and his dad. We get along well enough, but the one thing I am coming to you guys about is that my fiance and I are planning a wedding. I am completely 100% atheist and very set in my beliefs. 

My boss on the other hand is VERY religious and regularly goes on tirades about religion and the state of America and so on and so forth. I grin and bear it, and I grew up in a very Christian household so I can fake it. He believes I am Christian although I have never said one way or the other and I have been fine with leaving it that way. The problem that is coming up in my life is that for my wedding, I do not plan to have a pastor marry us nor have the wedding related to religion at all.

As you can imagine, there is no way I can't invite him to my wedding. I am very involved with their family. He treats me like I'm his daughter (he's made a few slip ups saying stuff like "Thats what Dads do!") And he has on several occasions made comments about his own family having weddings like mine and how sinful and terrible those people are for "not having God involved in their union". I'm unsure on how to approach this because I don't want to lie on a day that means a lot to me and just have a pastor marry us to keep the peace but it would cause a lot of tension in my office if I don't.

What would you do in this situation?
<bot>: Im a closet athiest at work and my boss is extremely religious. I'm getting married in the future and I don't plan on having a pastor marry us. How to keep the peace in the office?