[doubleprimary]

I've been with a woman for 4 years. We're both now 37. For the first two years we dated intensely and we were a great couple. Her daughter just turned 1 when we started dating and she has been like a daughter since. I love them both very much.

We started having problems about two years ago. She'll gave reasons like I take her for granted, I'm not intimate, and I not comfortable around her inlaws, to which she is still very close (I've never been married). My problem is that we can't have kids and that has produced a great conflict: how can I love a woman, but fear that I might love her less without a child? Is this real?

We decided to break off the romantic part last March a year ago, but we have grown closer since. We live separately, we're not dating officially, and basically have a sexless family now (though we have sex once)...meaning we operate as a nuclear family during the day and sleep in different houses: her, her child, and I spending a lot of quality time together cooking, walking, movies, camping, etc... It was satisfying but we never talked about our future.

A few weeks ago I walked into her home (we share keys) and she was with another man. She had been with him for couple months without telling me. Of course I exploded and I wanted to end the relationship for breach of trust. Why couldn't she tell me that she needed something else and why not ask me for it?

She wants to remain best friends but have the option to see other people. I don't think I can be close to her if she is with another man. She skeptical about our romantic future (she'll say, tried it once and didn't work) but I think we could if we considered adoption. There's still a spark of attraction between us. Since the new man, I've made advances that she dismisses as merely jealously, testosterone, etc...

What am I to do? My intuition tells me to run away, but she says I can't do it because I'm equivalent to her daughter's step-dad. Another part of me wants to jump in completely and try to make it work. She wants to stay close, don't talk about each other's relationships, and gradually decrease our time together.