Sure, the occasional late night or weekend is sometimes an unfortunate necessity, but even then your manager should recognise that and let you take some time in lieu.
If you are regularly working 45+ hours a week, your position is under-resourced for what is expected. Talk to your manager. Either the work load needs to reduce, or you need additional people and/or skills/training to get the job done in a reasonable amount of time.
If nothing is done, leave.