It's always freedom.
If it is "entrapment" then it's entrapment by (choice). Clearly all relationships are "at will". No one is (stuck) with anyone. Couples breakup and get divorced everyday. Each of us is (free) to choose our own friends, lovers, and spouse. Most people are either where they (want) to be or believe it's in their "best interest" at a particular time. When someone feels entrapment it's a sign that they feel "powerless" about their circumstances which sometimes erodes self-esteem.
The beautiful thing about a door is it lets those who want in (in) and those who want out (out). Anyone who is unhappy in a relationship and chooses to stay is (choosing) to be unhappy.
Sometimes it's a matter of changing one's mindset. Work that you (choose) to do should NOT be lumped in with work required to sustain life. Entering into a relationship, getting married, raising children, planting a garden, buying a fixer upper house, or taking care of a pet are all examples of (work) that we (choose) and therefore should be viewed as a "labor of love". After all we (wanted) these things. They were not (required) for us to live. The mature and responsible thing to do is to nurture whatever you (choose) to have in your life. Entrapment is a state of mind.