<human>: Give me a shortened version of the text

Hi /r/relationships. I have a close personal friend who I met through work. This relationship is strictly platonic and I think we hit it off because we have very similar personalities and our work situation is very dysfunctional, we both need an ally in the office. We are both in committed relationships and it is very clear to us both that because we work together and I am not about to risk my marriage of nearly 3 decades it will never get physical. We get along well and can discuss freely any subject A to Z without any inhibitions.

In the beginning it was a two way street and we kept it light but the relationship has become increasingly one sided... as it turns out she has mom issues, dad issues, boyfriend issues, money issues, you name it she has it. Being older I am much more self sufficient and don't need much emotional support, to be frank it felt good to be asked my opinion and I liked that she trusted me and relied on my support but I feel like I have become her emotional dumping ground and I want out. Lately all our time together outside the office (lunch) is spent with her venting and me listening. We used to occasionally meet for drinks after work which I enjoyed but suddenly there is no time, she is "busy", "stressed" or "not feeling well"... 

I can't and won't continue a relationship where this happens. I feel like all friendships should be a two-way street between peers, both individuals should feel good about it and both should come away feeling like it is positive and time well spent. I like being a mentor, I like feeling needed but it's gone too far, how do I get out yet preserve the working relationship and keep my ally on the business end?

Please don't say I shouldn't have put myself in this position... duh, hindsight is 20/20. Fact is everyone needs friends, it is too bad everyone has a different definition of friendship.
<bot>: I have a co-worker who dumps her personal issues on me, how do I get out while preserving a working relationship?