Should I just walk away

Ok so Iam a 30+ woman who got involve with someone from work the problem is we been hooking up off and on for 15 years now we are friends that seem to find our way to each other when we're having problems in our relationships' it seems to happen every 2 to 3 years. we'll hookup for about 1mon 2 being the most but we've been thru different things ova the years.i left the job and came back and so have he multiple times. i finally ended my 11 year relationship and he is still with his girlfriend. but we been hooking up for the last year he even chose to be with me sexually on his b-day which was 2 days ago. we dont really talk about us because we are just suppose to be friends with benefits. but i've really falling head over hills for him this last year. im just confused a year of sleeping with someone is more than just friends to me or maybe im wrong am i setting myself up for major heartbreak?

You'll find it extremely difficult to be with someone long term if they are still with their GF but use you for sex. If you're ok with this scenario, then you'll never be with him properly because you won't commit to you regardless if you've really fallen in love with him. If you're friends with benefits, then so be it, but don't expect a full on relationship if you both have been doing this for years while still with someone else. If you're questioning your 15 year old on/off casual relationship with this guy, then that's all it's was ever going to be.

If your expectations from the relation is increasing while his remains the same, it means its best to walk away to avoid being further hurt.

The reason you and this guy worked in the past was because there was no commitment .... you both could detach yourselves.... as you both were already in relationships.... Bear in mind here that only one thing changed..... that is you becoming single so you are giving more to him now...... and he is actually tow timing both of you..... only you are not this time as you are split.... I think you are going to be badly hurt here ......

thx u all for the advice... but i just sum the story up. its more to it like he ask me last year what i wanted to see happen with us and i told him i wish we could be more he said he felt the same way but was gone let nature take her place. and we were broken up with our significant others when we hook up.but then went back.my relationship was very crappy i wanted out badly he was an alcoholic.so he knew wat i was goin thru.it was up to me to leave.so as far as him staying with his girl sometimes people get comfortable and not wanting to start over.but we share a lot of interesting conversations as well as sex.just not about us so i dont see him as using me. i do think we need to finally talk. the one thing i cant handle is us not being friends.and if he really loved this girl y he have'nt wife her.she seems to think that just because they been together 11yrs also. he aint going nowhere.but i thk he stay with her because she dont have baggage/kids.where as i have 3 so thats the only reason i thk. but i ended my 11yr relationship 4yrs ago. so it can be done.but anyway i no wat to do iam just scared of the outcome. cause i actually do believe he want to be with me but men seem to let their pride stand in the way even at the age of 36.and also iam having a hard time tryin to figure how to start off the coversation. cuz he probably wouldnt ever imagine it.