Is it cheating or not?

[AmandaP]

I've being with my partner for almost 5 years, we have been living together for 4 years and have a 4 month old. I don't have the best self image and tend not to come of of my shell unless I'm drinking. When I do however I love the person that I become. I suddendly have confidence and really love being around people. (Now by drinking I don't mean writting myself off and getting s*** faced I mean enjoying a good bottle off wine with freinds)
When I look at a person I don't see then as male or female I just see a person. I have had relationships with both male and female partners. I spent a long time in open relationships and having one night stands. I don't think of sex as some thing private or intimate, I believe it is just a physical act.
I love my partner and him only, I plan on spending the rest of my life with him. I do (and have had all of our relationship) plan on having sex with other people. My partner and I don't talk about it and never have talked about it, I am sure however that he knows about it and understands that for me it is only a phyiscal act and that I love only him. I am curious what others think about this, IS IT CHEATING OR NOT?