Advice on Moving Forward

31M, 29F. We recently broke up after I found out my partner lied about sleeping with someone during a previous breakup. She has continued talking to this person for years and couldn't even say for certain whether there was overlap with our relationship. Given my history of being cheated on and a previous partner's dishonesty nearly resulting in an STI, I had been very open with her about how important honesty and trust are to me.

I don't care that she was with someone while we were officially broken up; it's the years of deception, continued relationship with this person, accusations that I was doing the same thing, and other boundary issues that destroyed my trust. At this point I consider it emotional cheating and I'm done.

She's now saying I'm not taking accountability and asking why I'm doing this to her because I need distance. I'm not denying I've made mistakes, but I don't understand how I'm supposed to take accountability for her actions. We also just moved into a house together, so now we're stuck figuring out the lease. She says I need to find a roommate or we both need to pay to get out, which feels unfair since we're both on the lease.

I don't have much of a support system and haven't gotten a new therapist yet. Looking for outside perspectives on the relationship/betrayal and especially advice on handling the shared lease.