I have a couple of female friends who steadily date their "boyfriends". I was invited to a party by one of these women. It was Sunday night, Labor Day weekend and I had nothing to do. They had been drinking all day long and they were offering booze quite freely. I was enjoying the beautiful evening on the Boston waters looking at the skyline of Boston. Then the girlfriend of the guy throwing this party sat down next to me and I asked if I was having a good time and I replied that I was enjoying myself quite a bit. She asked me what I thought about her boyfriend and I told her he was ok but was such a blatant womanizer I didn't know how she could handle it. She then explained to me that she certainly is not into a relationship "forever" with this guy but he's fun, the sex is great and if and when something better comes along she'll look into it.
Her girlfriend is a 47 year old woman who "sees" a "friend" usually two or three times a month and has sex with this guy and they have an agreement---they can see and sleep with anyone else they want with no strings attached. Of course the guy digs this arrangement and they never see each other in a social environment----only for sex. The woman has mostly male friends but only sleeps with this one guy (because she hopes he'll only want her which isn't happening as of now).
The bottom line is that I see a lot of men and women who date but certainly not with the intent of being 100% exclusive. I see women who are with other men, husbands or boyfriends, and openly flirt, not seeming to care about their men's feelings. And most men and women I know will have a one night stand if the circumstances are just right.
Honestly, if you were dating, would you be 100% committed or would you keep your options open???