I feel for you, brother. I too have spent way too much time and energy trying to keep WGF and OM apart and all my efforts were wasted. The cold hard truth of it is this, if she wants to see him then she will.
If not this weekend, then next, or late one night, or if you go on a business trip. There is ZERO stopping a WS from doing anything. Z-E-R-O.
Get out, enjoy some time with DD, try to feel normal even if it's just for the weekend.
There are plenty of folks here with great advice for you. There will be some bitter pills to swallow but we all want to help you minimize the pain and move forward in a healthy way.
VARs help. Hide multiple if you can (just don't tape them under a counter, WGF found mine almost as soon as i left the apartment ).
Me: BBF (29)
WXGF: Confused26 (27) EA/PA with xBF, lasted almost a year. TT, blameshifting, gaslighting, & broken NC for 10 months.
Together 5 years
3+ years later and I am doing great! Hell of a ride but well worth it.